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Posted: Jun 5, 2024 at 17:03 Quote
SleepingAwake wrote:
couple years in the making, but I think I'm done?!

Been slowly following the bits you drip-feed us on this.
It looks great and has amazing attention to detail.

Posted: Jun 5, 2024 at 18:49 Quote
I started following this forum expecting steel hardtails, and nothing against steel hardtails, I have one and would be happier than a dog w 2 tails if i could build one myself, but the level of complexity and engineering on display w bikes like sleepingawake and mrti is just unreal. Never in my widlest dreams did I think people could make bikes like this at home.

Posted: Jun 5, 2024 at 18:54 Quote
SleepingAwake wrote:
couple years in the making, but I think I'm done?!

It never ends. Great work!

It would be nice to see a print along with the pics.

Posted: Jun 5, 2024 at 22:42 Quote
Thanks everyone for the nice words!

skimgosu wrote:
Very cool! Seems like carbon front triangle and seatstay with 7075 chainstay and linkage? Curious what bearing sizes you are using and what your kinematic goals were.

seattays are carbon as well actually, but yeah, not a tubular structure but machined instead. All the rest is 7075-T6. The main pivot bearings and the rocker link main bearings are 6003 LLU max, seatstay/chainstay bearings are doubled up 6901 LLU max, and on the rocker link on the chainstay side doubled up 6902 LLU max. Tried to get really beefy bearings in everywhere.
In terms of kinematics I wanted to have something with about 25% progression and something that remains easy to tune without any weird transitions in the motion ratio. wanted to have really rearward axlepath, about 120% of antisquat around the sag-point and nearly no chain growth. I was slightly worried about the really high anti-rise values of my design, but at least in the low traction conditions we have right now it does not seem to be a problem.

pvd666 wrote:

It never ends. Great work!

It would be nice to see a print along with the pics.
Thanks, means something coming from you! I am working on a write up and will share here when it's done!

Posted: Jun 5, 2024 at 23:13 Quote
Some brands are selling worse bikes than that ! The level of details and quality is amazing !

Posted: Jun 6, 2024 at 5:37 Quote
SleepingAwake wrote:
seattays are carbon as well actually, but yeah, not a tubular structure but machined instead. All the rest is 7075-T6. The main pivot bearings and the rocker link main bearings are 6003 LLU max, seatstay/chainstay bearings are doubled up 6901 LLU max, and on the rocker link on the chainstay side doubled up 6902 LLU max. Tried to get really beefy bearings in everywhere.
In terms of kinematics I wanted to have something with about 25% progression and something that remains easy to tune without any weird transitions in the motion ratio. wanted to have really rearward axlepath, about 120% of antisquat around the sag-point and nearly no chain growth. I was slightly worried about the really high anti-rise values of my design, but at least in the low traction conditions we have right now it does not seem to be a problem.

At first glance, I thought the lower stay was 1-piece. I'm guessing you doubled up on the 6902 because you don't have a bridge on the lower stays? Curious why you didn't bother with a 1-piece lower stay.

Also, do you have a inner race spacer on the main pivot?

After putting your frame into linkage, some interesting questions came to mind:
1) Anti-squat is quite low on the bottom half of the cassette and even goes negative for the highest two gears; I'm curious how that felt. I'm sure the negative pedal kickback felt great regardless!
2) Anti-rise indeed starts high but drops quite a lot; did you notice this change from +100% to sub30% during descents? I've had a few riders blind test flat 30% and flat 0% anti-rise and they noticed the change!

edit; 80deg SA! How does the seated climbing position feel? Did the small TT bother you?

edit2; congrats on the prototype. Going thru the album, it's been quite the journey!

Posted: Jun 6, 2024 at 9:55 Quote
skimgosu wrote:
At first glance, I thought the lower stay was 1-piece. I'm guessing you doubled up on the 6902 because you don't have a bridge on the lower stays? Curious why you didn't bother with a 1-piece lower stay.
yeah two individual stays, but the axle connecting them is mechanically keyed into the stays to increase torsional stiffenes a little. And yes with the double bearing arrangement the system is overconstrained, but at that length of the individual members that shouldn't matter.

skimgosu wrote:
Also, do you have a inner race spacer on the main pivot?
There is an expander bolt on either side that locks it in place. No spacer

skimgosu wrote:
After putting your frame into linkage, some interesting questions came to mind:
1) Anti-squat is quite low on the bottom half of the cassette and even goes negative for the highest two gears; I'm curious how that felt. I'm sure the negative pedal kickback felt great regardless!
So according to my linkage file the anti-squat is never negative and between 105 and 140% depending on gear at sag (this is with my exact center of mass). Honestly not super happy with this large of a spread, but this was the best I managed to do, and I think it is adequate for the bike it is, and this week I felt still great after 1000m of vertical. It is heavy tho! These idler designs are very sensitive to the placement and I don't think a side picture is good enough to accurately tell the story.

skimgosu wrote:
2) Anti-rise indeed starts high but drops quite a lot; did you notice this change from +100% to sub30% during descents? I've had a few riders blind test flat 30% and flat 0% anti-rise and they noticed the change!
I only ever rode it in very greasy conditions, so with the limited traction all I noticed for now was that I didn't notice anything that felt strange. But it's early days...

skimgosu wrote:
2) edit; 80deg SA! How does the seated climbing position feel? Did the small TT bother you?
I am riding a XL Rallon with 480mm reach, and I as like long bikes I increased the reach by 15mm to 495, but kept the same distance from middle saddle rail to upper head set cup the same with the idea that it would feel pretty similar seated. However, it felt very different and a lot shorter than the reach suggests, and at first I said I overdid it with the seat angle. But by now I am not so sure anymore. time will tell

skimgosu wrote:
edit2; congrats on the prototype. Going thru the album, it's been quite the journey!
a journey it was. this project was above my pay grade for most of the steps and it feels like i made every part at least three times. But professionally or private this is by far the project I have learned the most! thanks for all the detective work Smile

O+
Posted: Jun 6, 2024 at 16:46 Quote
SleepingAwake wrote:
couple years in the making, but I think I'm done?!
well f*ckin done! Second the desire for some documentation of the process / details if you have any.

Posted: Jun 7, 2024 at 6:17 Quote
SleepingAwake wrote:
yeah two individual stays, but the axle connecting them is mechanically keyed into the stays to increase torsional stiffenes a little. And yes with the double bearing arrangement the system is overconstrained, but at that length of the individual members that shouldn't matter.
I've yet to implement keyed interfaces without clamping forces due to fears of contamination and creaking. What shape did you decide for the keys? I'd imagine quite the tight tolerance too, unless there are hidden expanders down there too!

SleepingAwake wrote:
There is an expander bolt on either side that locks it in place. No spacer
How do you preload the bearings?

SleepingAwake wrote:
So according to my linkage file the anti-squat is never negative and between 105 and 140% depending on gear at sag (this is with my exact center of mass). Honestly not super happy with this large of a spread, but this was the best I managed to do, and I think it is adequate for the bike it is, and this week I felt still great after 1000m of vertical. It is heavy tho! These idler designs are very sensitive to the placement and I don't think a side picture is good enough to accurately tell the story.
I mistakenly attached the idler onto the wrong element. Now I see how tight the AS spread is but also much higher PKB. Half a milimeter off the mark and it's a different bike!

SleepingAwake wrote:
I am riding a XL Rallon with 480mm reach, and I as like long bikes I increased the reach by 15mm to 495, but kept the same distance from middle saddle rail to upper head set cup the same with the idea that it would feel pretty similar seated. However, it felt very different and a lot shorter than the reach suggests, and at first I said I overdid it with the seat angle. But by now I am not so sure anymore. time will tell
That's strange.. reminds me when i measured my XL Commencal DH at 460mm reach even though I used a lower A2C fork. Super confusing because the XL is supposed to be 495mm and the large is 470mm

SleepingAwake wrote:
a journey it was. this project was above my pay grade for most of the steps and it feels like i made every part at least three times. But professionally or private this is by far the project I have learned the most! thanks for all the detective work Smile
It's infuriating how small mistakes can completely derail progress. Whip Definitely not for the faint of heart! Beer

Posted: Jun 10, 2024 at 14:14 Quote
SleepingAwake wrote:
couple years in the making, but I think I'm done?!

wow...! that's really quite some build !!

Amazing job man. Salute

Posted: Jun 18, 2024 at 6:55 Quote
So my Oleo strut fork has finally reach a ridable prototype v1.0.
Plenty of "adjustments" along the way.
Manitou Mattoc Floating Oleo v1.0. Flo-Leo strut Built up from strut v0.7 running at 150psi 10 progression. With a secondary Dorado air leg set at 50psi irt with 0 tokens. 150mm 27.5 travel mode.

Anyone wanting to find out how it got here...
https://www.mtbr.com/threads/ive-got-a-really-stupid-idea-oleo-my-fork.1230277/

Still plenty of adjustments to go moving forward.
Just because you can, doesn't mean you should!
But its fun to prove people wrong! Drool

Posted: Jun 18, 2024 at 15:05 Quote
scar4me wrote:
So my Oleo strut fork has finally reach a ridable prototype v1.0.

Don't leave us hanging - how does it ride?!

Posted: Jun 19, 2024 at 16:00 Quote
R-M-R wrote:
scar4me wrote:
So my Oleo strut fork has finally reach a ridable prototype v1.0.

Don't leave us hanging - how does it ride?!
Patience.....
Just sorting my 27.5 front wheel first.
I'm itching to get these tested too!

Posted: Jun 19, 2024 at 16:30 Quote
I'm sure no one is more excited to try it than you, but that's not my problem, so hurry up! lol

Posted: Jun 20, 2024 at 17:34 Quote
R-M-R wrote:
I'm sure no one is more excited to try it than you, but that's not my problem, so hurry up! lol

Quick update... It works really well.

Have upped to 300psi in the strut, and kept 50psi in the Dorado air. Definitely needs the secondary air spring for the moment!

Feels very plush, possibly a little too active.
Can see this possibly diving a bit more than most under weight shifts. Need to have a decent off-road ride, and get some square edge hits into it to really feel how the blowoff transition feeds back into the rider properly.

I've also found the error in my modelling and corrected that. Shows my current implementation at 300psi is actually about half the pressure it needs to be for what I'm aiming for. So this also means I'll probably have to get rid of at least 1 freebleed port,

Really stupid mistake in unit conversions caused it.

I should've picked up on it when I re-checked the calcs for the 1/2in shaft of the rebound damper.
Sods law, that 1/2in shaft would actually be optimal for a 300psi working pressure.
Have drawn up rough plans for using this shaft as a V2.0, but I'll have to make the main sealhead as the plastic one on the comp damper makes me nervous at those pressures.

Time to go play crash-test dummy some more
:geekFrown y)


 


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