Tyres vs suspension

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flag Danzzz88
Posted: Mar 10, 2021 at 14:12 Quote
So I tried a cheap E bike for the first time today, only a £3000 random brand e bike with 150mm travel and very heavy and midrange Rockshox air suspension... But the thing is it had 2.8 Rekons on it.
Now my bike is an sb165 with 2.35 Magic Mary soft, a £1000 rear coil and 180mm ZEB and the cheap plus size tyres e bike put mine to shame over small bumps and curb size features... I couldn't believe how I spent so much on a fancy bike, suspension and wheels for some cheapo e bike to just instantly feel miles more cushy running much inferior suspension.
So the question is do 2.8 tyres really make that much of a difference that even with much crapper suspension they just ride miles nicer, or is it more down to the fact this bike was a tank at nearly 25kg..

Here is the bike in question https://www.halfords.com/bikes/electric-bikes/voodoo-zobop-e-shimano-full-suspension-electric-mountain-bike---16in-18in-20in-frames-181726.html

From a comfort perspective it put my bike to shame, geometry was pretty whack and sure at super high speeds the Yeti is miles more stable...but my god at 15mph or slower as I was trying it the thing felt so plush....kind of how I expected my suspension to feel when I spent thousands on it but didn't quite live up to it. What you normally feel as small bumps or what feels like tyre tread on my bike this other bike literally erased them like biking on marble. I don't know if this is the weight of the bike, the less aggressive tread or the larger tyre size or a combination if all the above. But if it's mainly tyre size I really want to try it.

Really thinking about going 2.8 front now and 2.6 rear, trouble is my rims are only 27mm internal, though they are Stans wideright so maybe they are equivalent to a bit more.
Looking at his bike next to mine the Reckons only looked about 5mm wider, my Magic Marys come out at 61/62mm wide on my rims so would guess his Rekon 2.8s were around 67mm wide.
But anyway I was amazed, a cheap no brand e bike a quarter of the price of the Yeti felt better than even some DH bikes in terms of bump eating comfort.

Will I notice the same gains if I go to 2.8? Would to 2.6 net me a noticeable improvement over the 2.35 Magic Marys that already come up wide for their size and is it possible this was also down to the 120 tpi casing on the Rekons? Currently looking at a 2.8 DHF or Vigilante, or another Magic Mary in 2.6 as I know Maxxis come up small and Schwalbe on size or bigger.
flag Explodo
Posted: Mar 10, 2021 at 14:34 Quote
Danzzz88 wrote:
So I tried a cheap E bike for the first time today, only a £3000 random brand e bike with 150mm travel and very heavy and midrange Rockshox air suspension... But the thing is it had 2.8 Rekons on it.
Now my bike is an sb165 with 2.35 Magic Mary soft, a £1000 rear coil and 180mm ZEB and the cheap plus size tyres e bike put mine to shame over small bumps and curb size features... I couldn't believe how I spent so much on a fancy bike, suspension and wheels for some cheapo e bike to just instantly feel miles more cushy running much inferior suspension.
So the question is do 2.8 tyres really make that much of a difference that even with much crapper suspension they just ride miles nicer, or is it more down to the fact this bike was a tank at nearly 25kg..

Here is the bike in question https://www.halfords.com/bikes/electric-bikes/voodoo-zobop-e-shimano-full-suspension-electric-mountain-bike---16in-18in-20in-frames-181726.html

From a comfort perspective it put my bike to shame, geometry was pretty whack and sure at super high speeds the Yeti is miles more stable...but my god at 15mph or slower as I was trying it the thing felt so plush....kind of how I expected my suspension to feel when I spent thousands on it but didn't quite live up to it. What you normally feel as small bumps or what feels like tyre tread on my bike this other bike literally erased them like biking on marble. I don't know if this is the weight of the bike, the less aggressive tread or the larger tyre size or a combination if all the above. But if it's mainly tyre size I really want to try it.

Really thinking about going 2.8 front now and 2.6 rear, trouble is my rims are only 27mm internal, though they are Stans wideright so maybe they are equivalent to a bit more.
Looking at his bike next to mine the Reckons only looked about 5mm wider, my Magic Marys come out at 61/62mm wide on my rims so would guess his Rekon 2.8s were around 67mm wide.
But anyway I was amazed, a cheap e bike a quarter of the price of the Yeti felt better than even some DH bikes in terms of bump eating comfort.

Will I notice the same gains if I go to 2.8? Would to 2.6 net me a noticeable improvement over the 2.35 Magic Marys that already come up wide for their size?

Bigger tires are good. I'd guess for a 2.8 you should run a 40mm internal rim. I know a 3.0 is great on a 45 internal rim.

For lighter riders, a 2.6 is probably a big tire and tires bigger than those have to be run at too low of a pressure to not be bouncy and then they lose stability.

The tires have to match the payload. I find 27.5x3.0 High Roller IIs at 15 psi on a 45mm internal rim are amazing for me at 205 lbs without gear. They really do make a lot of the trail just disappear below you.

All that said, are you sure that the suspension on the ebike wasn't just tuned with very little compression damping since you can fall back on the motor to negate suspension bob?
flag Danzzz88
Posted: Mar 10, 2021 at 14:42 Quote
No if anything the suspension didn't seen to even move, the chassis felt like a hardtail in that there was no weight shift, I imagine the damping or air pressure must have been pretty high as the guy is heavier than me and the e bike is nearly 10kg more. It definitely seemed like it was the tyres doing all the work but I do know extra frame mass can improve things quite a lot too.

Do you know if 2.6 feels close to 2.8? Or is there not enough difference between 2.6 and 2.35/2.4 to go removing an almost new tyre for no reason? Is this how 29ers feel also or is plus 27.5 plusher than 29 2.4? I've never tried a 29er but if it performs like plus tyres I regret my purchase lol
flag Explodo
Posted: Mar 10, 2021 at 15:20 Quote
I like my 27.5x3.0 tires a LOT. The tires weigh about the same as my 29x2.5 tires. They're about the same diameter as my 29x2.5 tires. There's no weight or diameter penalty. The rim/spoke weight is actually closer to the hub, so there's a a bonus. The biggest penalty is that the industry is moving away from 3.0 tires and 2.8 is the "big" tire they're keeping.

The 27.5x3.0 tire is much smoother than a 29x2.5.
flag Ontario123
Posted: Mar 11, 2021 at 4:39 Quote
I ride 2.8 rekons on my hardtail.

Super plush at lower speeds. The faster/harder you ride, the more air you have to add to keep the tire from bottoming, squirming, or rolling...

If you think of your tires like a part of your suspension, adding air increases the spring rate just like your fork or shock. As the spring rate (and potential to store energy) goes up, there's no "rebound" adjustment to keep the tires from bouncing back from big compressions. So at some point, there's diminishing returns with bigger tires.

In my experience, 2.6's and 2.8's ride very differently. A lot more volume with the true plus sized tires.
flag Danzzz88
Posted: Mar 11, 2021 at 5:04 Quote
Well I can't think of any other reason other than huge frame weight why a bike a quarter of the price and less travel would be miles smoother.
Going down rock stepped sections my bike was like a jackhammer on the front even with damping full open and only 18psi in the front tyre on a 2.4 mary. The E bike literally went down it like a motocross bike, no jackhammer effect, just supple all the way to the bottom like there was hardly any steps there.

If the difference really is that profound I don't know why not everyone is on plus tyres....I mean granted thet say pros prefer narrower to cut in and get grip and casing support bla bla bla, but thr 2.8 required so much less effort fighting against the jerkiness of the bike, rather than trying to fight it and support myself I just held onto the bars and went down like it was nothing on the ebike, I felt like a total passenger in comparison it was so much easier.

This I think had made me realise tyre pressures and rim width are much more important than fancy custom tunes and huge travel numbers.
flag DonLopez
Posted: Mar 11, 2021 at 5:44 Quote
The extra weight of the e-bike probably contributes to it feeling like a motocross bike. They make e-motocross too, just no pedals.

The smooth ride is a combination of the weight, tires, and suspension designed for that e-bike.
flag Danzzz88
Posted: Mar 11, 2021 at 7:08 Quote
So will 2.8 front 2.6 back get me closer to that feeling is the heavier mass the bigger factor than the tyre size?
flag Pigglet13
Posted: Mar 11, 2021 at 9:28 Quote
Danzzz88 wrote:
So will 2.8 front 2.6 back get me closer to that feeling is the heavier mass the bigger factor than the tyre size?

It might at low pressures and low speeds but then you will run into the negatives of that set-up as speed increases.
I know exactly what your talking about, I run a fat bike with 4.6 minions in the winter and at slow speeds, particularly on fist size rocky climbs and descents, the tyres just deform to absorb the rock and you don’t feel them.

The flip side to that is when you speed up its vague at low pressures and bouncy at higher pressures and on some terrain like slick off camber grass it’s terrifying!

The weight of e bikes deffimitely has an impact on their ability to smash down stuff and not get rattled about as you do on a lighter bike. I’ve ridden quite a few in various guises and that is a common trait to them all.

The bigger the wheel, the more it smoothes the trail if compared with like for like tyres so that is another factor to consider. I can’t compare my 38s with a 29” hoop to a zeb as I’ve never ridden one but mine are custom tuned and the small bump compliance is very good but not fat bike good on those knuckle size rocks at slow speed. It’s in another league of composure compared to everything I’ve tried except 40s at anything above walking speed though. RS small bump compliance is normally pretty good. How light are you, have you had them tuned?

I personally don’t like 27.5 plus, I found it offered the worst of both worlds, not as cushy as full fat and not as much grip and precision as a 2.4 to 2.6 29er but I appreciate it depends on how heavy you are and what/where you ride.

If you want to go fast in varied terrain and are a lighter rider I suspect 27.5 2.8,s may result in lack of cornering grip but there’s only one way for you to find out.
flag Danzzz88
Posted: Mar 11, 2021 at 11:05 Quote
Pigglet13 wrote:
Danzzz88 wrote:
So will 2.8 front 2.6 back get me closer to that feeling is the heavier mass the bigger factor than the tyre size?

It might at low pressures and low speeds but then you will run into the negatives of that set-up as speed increases.
I know exactly what your talking about, I run a fat bike with 4.6 minions in the winter and at slow speeds, particularly on fist size rocky climbs and descents, the tyres just deform to absorb the rock and you don’t feel them.

The flip side to that is when you speed up its vague at low pressures and bouncy at higher pressures and on some terrain like slick off camber grass it’s terrifying!

The weight of e bikes deffimitely has an impact on their ability to smash down stuff and not get rattled about as you do on a lighter bike. I’ve ridden quite a few in various guises and that is a common trait to them all.

The bigger the wheel, the more it smoothes the trail if compared with like for like tyres so that is another factor to consider. I can’t compare my 38s with a 29” hoop to a zeb as I’ve never ridden one but mine are custom tuned and the small bump compliance is very good but not fat bike good on those knuckle size rocks at slow speed. It’s in another league of composure compared to everything I’ve tried except 40s at anything above walking speed though. RS small bump compliance is normally pretty good. How light are you, have you had them tuned?

I personally don’t like 27.5 plus, I found it offered the worst of both worlds, not as cushy as full fat and not as much grip and precision as a 2.4 to 2.6 29er but I appreciate it depends on how heavy you are and what/where you ride.

If you want to go fast in varied terrain and are a lighter rider I suspect 27.5 2.8,s may result in lack of cornering grip but there’s only one way for you to find out.

Well I don't mind giving up a bit of cornering grip because the difference in stability, not getting rattled about as you say and not only plushness was 'huge'. I felt like all I needed to do was hold on and point where I wanted to go rather than fight the rattle and jackhammer of the bars.

My bike seems ok though not as good as the e bike when rolling up into stuff or over it but when it comes to ledges that drop down or stairs for example that's when it starts getting all rattly and harsh, changes in step height when going down seem to really upset it, but rolling forwards over stuff say a curb in the street it's not too bad. I mean I'm probably exagerating the jackhammer bit, my suspension is still good compared to some other normal enduro bikes I've tried but compared to the E bike with plus tyres, frankly it was a very big difference, like as big or bigger than going from air to coil whilst dropping a few psi out your tyres kind of difference. But what is more shocking is it's a cheapo e bike, if that Halfords brand e bike is that good, a Kenevo or something with 2.8 tyres would absolutely decimate my sb165 due to the longer travel, coil and equivalent geometry...annoying really as I was looking at them and the Zerode before I decided to just get the sb165.
flag Danzzz88
Posted: Mar 11, 2021 at 11:55 Quote
So I just lowered my tyre pressure to a stupidly low 13psi front and back and dropped fork 2 psi just to see how different it feels and it now feels much closer to the e bike, I'd say around 80% -85%=there or so in terms of plushness and rollover... Though what is lacking that wasn't on the ebike sidewall stability and squirm even at low to moderate speeds. But I just love that feeling where the tyres feel like they are almost like a baloon and you hear that little soft pop sound as you go over square edges and bumps....it really tames the rattling massively and feels more poppy and fun at the same time but unfortunately with my 27mm internal rims and 2.35 Magic Mary that psi is far too low to not bottom the rim out and corner agressively.

This is why I want to fit a 2.6 or 2.8 to see if I can get a bit more cornering support and suppleness at the same time rather than one or the other...I know my rims are considered far too narrow but wonderinf if I could get a 2.8 and at least just try how it feels first before relacing my already pretty expensive carbon wheels to some wider hoops?

What is the lowest width rim has anyone here tried with plus tyres with moderately successful results?

Also if I go with a softer casing while it negate the point of me running low psi for sidewall support? Would a tougher casing and low psi feel cushier than a lighter casing and higher PSI?
flag mtbtrekracer
Posted: Mar 11, 2021 at 13:09 Quote
its alot more to do with the weight. weight will always add stability but lose agility - think about that.
It's just like situation of how come Ebikes jump so well, the bikes weight will naturally preload jumps more etc.
flag R-M-R
Posted: Mar 11, 2021 at 13:28 Quote
• Yes, large tires really do improve suppleness that much. A tire's casing has essentially zero static friction to overcome and zero inertia to delay the movement.
• Yes, the added unsprung mass [EDIT: meant to say "sprung mass"] of an e-bike improves the feel of the suspension, but the difference is not as significant as going from 60 mm (2.35") to 71 mm (2.8") tires.
• The main downside is lateral stability (largely avoidable), followed by undamped rebound (partially avoidable), followed by mass (partially avoidable).
• Not all widths are accurately reported. I have a nominally 2.6" that measures 2.4" and another nominally 2.6" that's 2.75". I also have a nominally 3" that's the same as the oversized 2.6".
• Wide rims are necessary to support wide tires, especially with supple casings.
• Not all tread designs are well suited to wide rims. Most have insufficient wrap, leading to a frustrating situation in which you can have either sufficient lateral support or a tire that doesn't deflect off everything, but not both.
• A more robust casing on a wide tire can add lateral stability and changes the feel. It won't feel quite as "smooth", but it reduces the undamped rebound.

Regarding Stan's rims: There's nothing magic about Stan's WideRight that allows them to get away with the ratios they claim. The bead socket design helps a tiny bit, but the effect becomes less significant with wider tires because the effect of casing shape in the immediate vicinity of the rim is a smaller portion of the casing. Stan's claim their rims are suitable for a rim:tire ratio as low as 41%, while road bikes are now using ratios as high as double that, despite the narrow tires. Mountain tires and rims are going about it all wrong and Stan's is near the top of that list.

The wider the rim, the less the tire depends on high air pressure to maintain lateral stability. When the rim is too narrow, it is not possible to have a pressure that produces acceptable lateral stability and ride quality. When the tire is better supported by rim width, there is a broader range of acceptable pressure, including pressures low enough to produce the ride quality you're seeking.

Changes in tire width become less significant on wider tires. For example, the 10 mm difference between a 66 mm (2.6") and 76 mm (3") tire is only 15%, while adding 10 mm to a 20 mm road tire is an increase of 50%. The difference between 71 mm (2.8") and 66 mm (2.6") is perceptible (all else being equal), but it's not huge. Unfortunately, your 27 mm rims are too narrow to properly support a 71 mm tire, let alone anything wider. You could use a 71 mm Schwalbe with Super Gravity casing, but:

• The weight is most of a pound more than a Kenda Hellkat ATC, for example.
• As long as the rim is too narrow, the lower limit of your pressure will still be determined by lateral stability, not pinch flat protection. As such, the stiffer casing won't be much more supple.
• Seb Stott measured the 2.6" Magic Mary at 2.35" on a 30 mm rim. I don't know if Schwalbe has corrected this or maybe the Eddy Current 2.6" measures closer to the nominal size.
flag Explodo
Posted: Mar 11, 2021 at 13:55 Quote
R-M-R wrote:
• Yes, large tires really do improve suppleness that much. A tire's casing has essentially zero static friction to overcome and zero inertia to delay the movement.
• Yes, the added unsprung mass of an e-bike improves the feel of the suspension, but the difference is not as significant as going from 60 mm (2.35") to 71 mm (2.8") tires.
• The main downside is lateral stability (largely avoidable), followed by undamped rebound (partially avoidable), followed by mass (partially avoidable).
• Not all widths are accurately reported. I have a nominally 2.6" that measures 2.4" and another nominally 2.6" that's 2.75". I also have a nominally 3" that's the same as the oversized 2.6".
• Wide rims are necessary to support wide tires, especially with supple casings.
• Not all tread designs are well suited to wide rims. Most have insufficient wrap, leading to a frustrating situation in which you can have either sufficient lateral support or a tire that doesn't deflect off everything, but not both.
• A more robust casing on a wide tire can add lateral stability and changes the feel. It won't feel quite as "smooth", but it reduces the undamped rebound.

Regarding Stan's rims: There's nothing magic about Stan's WideRight that allows them to get away with the ratios they claim. The bead socket design helps a tiny bit, but the effect becomes less significant with wider tires because the effect of casing shape in the immediate vicinity of the rim is a smaller portion of the casing. Stan's claim their rims are suitable for a rim:tire ratio as low as 41%, while road bikes are now using ratios as high as double that, despite the narrow tires. Mountain tires and rims are going about it all wrong and Stan's is near the top of that list.

The wider the rim, the less the tire depends on high air pressure to maintain lateral stability. When the rim is too narrow, it is not possible to have a pressure that produces acceptable lateral stability and ride quality. When the tire is better supported by rim width, there is a broader range of acceptable pressure, including pressures low enough to produce the ride quality you're seeking.

Changes in tire width become less significant on wider tires. For example, the 10 mm difference between a 66 mm (2.6") and 76 mm (3") tire is only 15%, while adding 10 mm to a 20 mm road tire is an increase of 50%. The difference between 71 mm (2.8") and 66 mm (2.6") is perceptible (all else being equal), but it's not huge. Unfortunately, your 27 mm rims are too narrow to properly support a 71 mm tire, let alone anything wider. You could use a 71 mm Schwalbe with Super Gravity casing, but:

• The weight is most of a pound more than a Kenda Hellkat ATC, for example.
• As long as the rim is too narrow, the lower limit of your pressure will still be determined by lateral stability, not pinch flat protection. As such, the stiffer casing won't be much more supple.
• Seb Stott measured the 2.6" Magic Mary at 2.35" on a 30 mm rim. I don't know if Schwalbe has corrected this or maybe the Eddy Current 2.6" measures closer to the nominal size.

Figured you'd chip in eventually.
flag Danzzz88
Posted: Mar 11, 2021 at 14:02 Quote
R-M-R wrote:
• Yes, large tires really do improve suppleness that much. A tire's casing has essentially zero static friction to overcome and zero inertia to delay the movement.
• Yes, the added unsprung mass of an e-bike improves the feel of the suspension, but the difference is not as significant as going from 60 mm (2.35") to 71 mm (2.8") tires.
• The main downside is lateral stability (largely avoidable), followed by undamped rebound (partially avoidable), followed by mass (partially avoidable).
• Not all widths are accurately reported. I have a nominally 2.6" that measures 2.4" and another nominally 2.6" that's 2.75". I also have a nominally 3" that's the same as the oversized 2.6".
• Wide rims are necessary to support wide tires, especially with supple casings.
• Not all tread designs are well suited to wide rims. Most have insufficient wrap, leading to a frustrating situation in which you can have either sufficient lateral support or a tire that doesn't deflect off everything, but not both.
• A more robust casing on a wide tire can add lateral stability and changes the feel. It won't feel quite as "smooth", but it reduces the undamped rebound.

Regarding Stan's rims: There's nothing magic about Stan's WideRight that allows them to get away with the ratios they claim. The bead socket design helps a tiny bit, but the effect becomes less significant with wider tires because the effect of casing shape in the immediate vicinity of the rim is a smaller portion of the casing. Stan's claim their rims are suitable for a rim:tire ratio as low as 41%, while road bikes are now using ratios as high as double that, despite the narrow tires. Mountain tires and rims are going about it all wrong and Stan's is near the top of that list.

The wider the rim, the less the tire depends on high air pressure to maintain lateral stability. When the rim is too narrow, it is not possible to have a pressure that produces acceptable lateral stability and ride quality. When the tire is better supported by rim width, there is a broader range of acceptable pressure, including pressures low enough to produce the ride quality you're seeking.

Changes in tire width become less significant on wider tires. For example, the 10 mm difference between a 66 mm (2.6") and 76 mm (3") tire is only 15%, while adding 10 mm to a 20 mm road tire is an increase of 50%. The difference between 71 mm (2.8") and 66 mm (2.6") is perceptible (all else being equal), but it's not huge. Unfortunately, your 27 mm rims are too narrow to properly support a 71 mm tire, let alone anything wider. You could use a 71 mm Schwalbe with Super Gravity casing, but:

• The weight is most of a pound more than a Kenda Hellkat ATC, for example.
• As long as the rim is too narrow, the lower limit of your pressure will still be determined by lateral stability, not pinch flat protection. As such, the stiffer casing won't be much more supple.
• Seb Stott measured the 2.6" Magic Mary at 2.35" on a 30 mm rim. I don't know if Schwalbe has corrected this or maybe the Eddy Current 2.6" measures closer to the nominal size.

Thanks R-M-R...that is all the info I was exactly looking for so cheers for that lengthy response.

Now to a somewhat intermediate solution until I decide what to do with my rims... You say the Seb measured the 2.6 at 2.35 and I remember seeing that but weirdly even on my small internal rims my Magic Mary 2.35 blows up to at least 60mm, almost 62m knob to knob... The Rekon 2.8on the other bike next to mine did look bigger but judging by eye I'd have to say it looked about 5mm wider, which funnily enough puts it exactly at the stated 67mm Maxxis says if I my Magic Mary size is anything to go off.


So I'm guessing the new 2.6 Magic Mary comes up small and won't make much difference... Would it be worth at least trying a DHF 2.8 on my rims just to see the difference or is it not really going to do much? I mean if I run a thinner tyre at higher PSI surely it's less squirmy than a larger tyre at lower PSI...though for equivalent plushness the larger tyre needs to be run lower pressure to feel as soft due P=F/A and all that...
Tbis would suggest to me that to run larger tyres you need significantly largely rim width as not only do you have to run much lower pressures for the same overall harshness but you also have less sidewall support and in most cases much thinner sidewalls.


So on that note, do you know of any recommendations I can try on my current rims with reasonable success to get somewhat of a flavour for the ride I am looking... Something that will be a noticeable improvement over my 2.35 Magic Mary's in soft? I'm not fussed about tread pattern and compound etc for grip and cornering, just more looking for a plusher larger tyre to experimwnt trying the larger casing and see how close I can get to that damned £3000 Ebike XD
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