Renthal 40mm Duo Stem - Review
Pinkbike Product Picks
![Renthal 40mm Duo stem - reviewed 2014]()
Renthal 40mm Duo Stem
Renthal's Duo stems are unique in that the main body of the stem is manufactured in two pieces. By splitting the stem vertically in this manner, they can machine the interior of the stem to a greater degree than is possible with a standard, front-loading design. The results are compelling, the 40mm Duo stem weighs just 124g, but is strong and stiff enough for whatever abuse you might want to put it through. Renthal also claim that the design and shape of the clamping area puts less stress on your handlebar. Until now they were solely available in a 50mm length, but with the rising popularity of big-wheeled bikes and long front-centers, they have produced a 40mm version, with a ten-degree rise. It is only available in a 31.8mm clamp, as Renthal don't see the need for 35mm diameter bars. They feel their bars are already strong enough and while some companies can decrease the handlebar weight with the larger diameter clamp area, there is a corresponding increase in stem weight that is often overlooked. MSRP: $99.95 USD.
Renthal
![n a]()
Pinkbike's Take:
Renthal 40mm Duo Stem
Renthal's Duo stems are unique in that the main body of the stem is manufactured in two pieces. By splitting the stem vertically in this manner, they can machine the interior of the stem to a greater degree than is possible with a standard, front-loading design. The results are compelling, the 40mm Duo stem weighs just 124g, but is strong and stiff enough for whatever abuse you might want to put it through. Renthal also claim that the design and shape of the clamping area puts less stress on your handlebar. Until now they were solely available in a 50mm length, but with the rising popularity of big-wheeled bikes and long front-centers, they have produced a 40mm version, with a ten-degree rise. It is only available in a 31.8mm clamp, as Renthal don't see the need for 35mm diameter bars. They feel their bars are already strong enough and while some companies can decrease the handlebar weight with the larger diameter clamp area, there is a corresponding increase in stem weight that is often overlooked. MSRP: $99.95 USD.
Renthal
Tech aside, we love how the Renthal stems look and somehow they seem to look good on any bike.
Pinkbike's Take:
 | There are two main groups of riders that this stem will likely appeal to, riders who are looking to run a longer top tube to increase the wheelbase, or riders with bigger-wheeled bikes who want to sharpen their steering. We ended up falling into both of these categories, running it on a bigger-wheeled bike with a longer top tube. In terms of handling, the difference between a 40mm and a 50mm stem is small, but if you follow the logic that a 650B bike is slightly slower handling than a 26" bike, that small difference is enough to make the bike feel sharper. In terms of quality, we simply cannot fault Renthal Duo stems, we have had them in circulation on test bikes and personal bikes since 2011 and haven't had any issues. We do sometimes see reports that people having creaking from their stem, but that is an installation issue and tightening the bolts further fixes it in our experience, although you'll want to be sure not to exceed the recommended torque spec. Greasing the bolt threads should also help to silence any noise. To sum the stem up, it is light, stiff, we love the way it looks, and for a top-end, UK-made stem, the pricing is sensible for this kind of quality. - Matt Wragg |
Author Info:
Must Read This Week
[UPDATED] Final Elite XC Results & Overall Standings from the Mairiporã XC World Cup 2024
42203 views
42203 views
Sign Up for the Pinkbike Newsletter - All the Biggest, Most Interesting Stories in your Inbox
PB Newsletter Signup
www.ebay.co.uk/itm/111348253613?_trksid=p2055119.m1438.l2649&var=410331226399&sspageName=STRK%AMEBIDX%3AIT
It will, and it will get even faster, such is innovations want.
Since we cannot ever hope to reign in the speed at which it operates, it leaves us with only one question: How do I want to respond to the latest innovation?
Choose your time, your reason and your place and all is bliss on your bike.
Case in point, I ride 26, single narrow wide ring, 9 speed. That will change at some point, but not now. Enjoy.
You should be using anti-seize rather than grease on the bolts, prevents galling, and doesn't break down like grease will over time, whether it creaks or not, you should be using good anti-seize.
"although you'll want to be sure not to exceed the recommended torque spec" - I swear that I did not read that originally and it has been added in, anyway, drama over.
Is it really an "upgrade", or are you just playing straight into the hands of good old marketing technique?
With all that said, I am very happy with my Renthal handlebars, and I am looking to get the Duo stem too sometime in the future.
I do not think that 35mm bars is necessary and I sure do not consider 35mm to be an upgrade.
(A part of me still miss the good old days with the 25,4mm handlebars.)
However, soon there will be non-DH/FR 35mm stems available. There are some trail/xc 35mm clamp stems just about to hit the market. Easton has announced and will soon be shipping a 35mm haven stem and RaceFace has done the same with their turbine stem. Within a year, we should see many more of the lighter weight stems brought to the 35mm clamp size.
35mm would be better if designing standards from scratch today. It is debatable if switching to a new "standard" is worthwhile, but it is superior from a weight/strength perspective.
Because tapered steerertubes, 15mm drop outs, press fit bb's, 27.5" wheels, 29" wheels, etc, etc wasn't enough
Big props for Renthal for not jumping on the bandwagon and creating products that riders actually want! We need more companies like Renthal, and less BS companies that shove their shit down our throats.
Hint, he uses the M*** S****** word.
35mm is pretty awesome. We have issues with the wheel standards and fork standards as they really limited the second hand market for many other genre's of biking, such as DJ and Street where all headtubes are standard, or at least the vast majority of them are. As companies are already making 35mm bars of all geometries, it's not as if anything is lost by this standard coming out, just a better cockpit.
Please do try to think before bitching about what companies are putting out. Sure, useless tech and needless innovation harms cycling, but progress that is actually beneficial with little to no consequence should be openly accepted into bikes, not cast down in the same sentence as some recent buzz news about a company that isn't even relevant.
I like it when i can swap parts around bikes, sure. But I don't expect a Suzuki exhaust to fit a Honda or a GM cylinder to fit a RAM truck.
And WTF does Specialized litigation got to do with any of this? You're like the crazy person that used to sit at my train stop and argue with no one at all.
I agree I overreacted with my rant, but I'm still mad at companies that screw people over by creating new standards that don't improve anything, but force people to replace several parts when only one part needs to be replaced.
A good example is the tapered forks, if you want to replace your current fork with a new one, you will also have to ditch your current frame that's all good, and spend another $400-3000 bucks just so you can fit that new fork. While 1 1/8" forks have always proven to be strong enough. I might aswell just set that money on fire and watch it burn. Same if 35mm becomes the new standard: if you replace your bars you can ditch your stem aswell and spend another $40-100 bucks on nothing just so you can fit your new bars. While 31.8mm bars and stems have always been working perfectly.
Many pro slopestyle riders even ride 25.4mm bars and huck bigger stuff than pretty much any of us would do.
- hard tail to soft-tail = massive improvement (depending on terrain)
- thin tires to high volume tires = massive difference
- v brake to hydraulic brake = massive difference
- 9mm to 20mm axle = marginally noticeable improvement
- straight to tapered steerer = no/hardly any difference found
- 26-27.5 wheel size = no/hardly any difference found
- Any BB to pressfit = worse
-31.8 bar/stem to 35mm = laughable
Glad to see there are still a few ppl out there who can see through the marketting crap and actually tell a real improvement from some made up money spinning trinkets.
Taper forks are a great example. It allowed companies to use larger diameter bearings for longer life and reliablity, it made the forks stronger, I'm sure a few people could give you examples of straight sterrer 2011+ 36's with broken steerers, but the taper ones seem to be holding up. No benefit there? The real issue is frame companies (DJ companies mostly) refusing to get onto the new standard. It's been like, 4, 5 years since it came out? No excuses any more. Catch up with the market. Deity showed shots of a taper cryptkeeper at sea otter. That's where we need to be, not bitching about something that gives a benefit, even if it's small.
TL;DR, you know you don't have to buy 35mm as there are still 31mm options on the table, hell, there's still 25mm options on the table. Complain when it's actually cutting into a market segment, such as taper was for DJ bikes, not when it's a developing standard that has absolutely no bearing or negatives to you.
And lastly, 9mm to 20mm was a MARGINAL improvement? What the f*ck planet do you live on buddy? 20mm is a MASSIVE improvement in both rigidity and strength over a QR axle.
Maybe you hate motos and love stupid box vehicles but ALL the freaking technology that you love so much comes from motos. So if you don't like motos go and throw away your modern mountain bikes. Like hydraulic brakes? Chuck them, just miniaturized moto technology. Also throw way your wide bars, coil suspension, chain guide and tubeless tires while you are there. Oh and those 40mm fork stanchions you love so much......guess where they are from!
As for the whole "should heavier bikes have thinner bars" question. Yes. Yes they should. Cos then you can have thicker tube walls. Has been my point all along. 35mm flexy bars are fine for an xc bike, and good cos they do indeed weigh bugger all. Just wouldn't like to ride a damaged set...
Yes bikes are evolving sherbet, but not EVERY new thing is an improvement. In fact well over 50% of it is either a downgrade or a sideways step. Some people find it hard to tell the difference which is why its good to come on here and read all the comments, as often hidden in amongst the idiocy, pointless fanboyism and sarcasm there are little gems of wisdom. Often from the most unexpected sources.
Weight is relative
Stiffness is relative
Stability is often not duscussed.
I ran Eastons alloy 800x35mm x 35DM stem on 40s on my V10c the Stability gains tracking control on the DH track was massive, Im tslking about muppets rifing DH bikes with plush slow setups on trail bike trails. Proper DH
I now have testing Chromags BZA stem bar combo in 35mm std on my trail/enduro bike and the carbon bar is very good for dampening vibration but stiff and stable as hell it will become mainstream once people pull theyre heads out of theyre arses!
This same BS discussion happened when we went from GHEY mtb roadie 25.4mm 680 wide std to 31.8mm 710mm width stds
If u ride slow plush and flexy is good, full frontal speed requires stabilty!
OTA people. ...
Looks like a f*ckin frog.
And if you lose 1 bolt ona normal stem you have 3 more holding it on , not a 3-4mm bit with one bolt
Matt, what you were probably noticing is that the first batch of 35mm products on the market were designed to be stiffer than everything else. However they don't have to be designed that way. Lots of new 35mm products are now coming to market that shed some weight and stiffness. They are probably more suitable to your preference in bar stiffness. For example, compare the raceface next SL bars to what you rode previously. At only 180g for 760mm wide, they might be just what you're looking for.