Home Made Bikes

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Posted: Jan 22, 2018 at 2:20 Quote
You raise a good point, always consider things as +- from the sag point, after all that is where it will be when your sat on it. In this case I only took a quick look at work and didn't consider it which is my failing.
From the sag point it is quite linear so might actually be ok with the air shock.
But it ramps up a lot to the sag point (expecting ~40mm) which is what makes me wonder if it is too much. I'm not actually sure how such a rapid change in rate would feel before the sag point.

It cannot be ignored as it helps dictate how the bike will feel when high in the travel (under hard front braking, when flicking the rear about, over whoops etc.) in a similar way that the very slow hydraulic topout on the 5th element shocks made a lot of bikes feel dead even though it only effected the last 5-10mm of shock travel, in this case my concern would be that it could make the bike feel very soft, almost flat tyre like.
One way to put it would be the feeling you get if a shock collar is not seated against the spring leaving some slack extension of the shock, that sort of baggy feeling as you would be setting the air pressures to give correct rate at the sag point with it getting rapidly softer before that point.

Can't say for sure as rate changes like that are not that common for obvious reasons, there are bikes out there with similar changes, anyone have any first hand experience with this?

nitzsche wrote:
Check the sag point, looks pretty progressive, almost too much, but if your sag point its ok it could work

l-plates wrote:
I like your linkage design and thinking, it's going to help stiffen the rear end as well as adjusting the leverage in a very compact and neat package.

I do wonder if you might have too much progression in the first section and maybe too much overall for an air shock (which are naturally quite progressive but modern shocks are better in this regard).
As a comparison my DH bike drops from 2.95 down to 2.5 over ~160mm before leveling off in a similar way, this has provided plenty of progression with a coil shock.

How do other air shocked 140mm bikes compare?
Perhaps someone else with more experience on the short travel stuff could confirm but my experiance has been that air shock stuff tends to keep to a change of no more than 0.3, to me it looks like a good curve and a good point for the progression to level off but perhaps a little too much over all progression?

With the current leverage rate you may find it a little soft for a short travel bike in the early region or a bit harsh when deep in the travel.

Posted: Jan 23, 2018 at 3:40 Quote
Custom built DH prototype

Finally my bike is built ! yaaay !
super excited, need to build it up soon !
Psynyde Dioxide

Thanks for viewing everyone !

Posted: Jan 24, 2018 at 16:32 Quote
Steel DH bikes FTW

Posted: Jan 25, 2018 at 6:42 Quote
Holy cow guys we need some more pictures of those two sleds! They're amazing!

Posted: Jan 25, 2018 at 7:12 Quote
SleepingAwake wrote:
Holy cow guys we need some more pictures of those two sleds! They're amazing!

Just built up my bike. Frame accepts a 27.5, but my fork doesnt. So assembled it with my 26er wheelset.
Hope you all like it !

Thanks !

Posted: Jan 26, 2018 at 12:20 Quote
smith931 wrote:
jamiebiker wrote:
hi i am making this thread so that people with home made frames can show there designs

********EDIT BY MODERATOR***********
-DRACO-

I have added a couple pics from page 261 right at the beginning so you can see what we are talking about!

draco wrote:
Considerations for design- seriously, guys, there is a ton of things you need to consider/keep in mind and think about.

Once i was happy with the angles and geometry, and had the linkage worked out, it was time to figure out how the frame was going to be built. Tube placement, diameters, angles of the tubes that dont affect geometry.. etc.

The lower rightmost one above was the final.

So then you check axle path and tire clearance.

Then you check chainstay clearance, chainring clearance, crankarm clearance, chainguide clearance.. eeeeesh

Then you design pivots!

Then you design a jig to hold the pivots in place!

Then a jig to hold the frame in place.

Then you're more on your way.

lotta stuff to consider!

Wow dude, I am really surprised, what’s you have done. Hopefully we will see an awesome bike from your own design. Just carry on…

Which program is this? Seems to be popular for 2D design

Posted: Jan 26, 2018 at 12:22 Quote
Looks a little like libreCAD

Posted: Jan 27, 2018 at 12:45 Quote
Looks like AutoCad?

Posted: Feb 9, 2018 at 12:26 Quote
[Quote="MTBLegend92"]
findhan wrote:
Hello guys, havent posted here in a long time: looking to make a single pivot frame to get back in the game and keep things simple. Im thinking of putting a Shimano 1x11 drivetrain on it (SRAM too pricey for prototypes!!) Probably M8000, 32 chainring, One of the areas I have struggled with in the past is getting the rear end chainstays sorted - so could anyone hit me up with some CAD models, 2D or 3D or even specs from Shimano on crank, chainring and hub dimensions or the likes? Is there anywhere where this is all in one place? 27.5 inch wheels with Boost 148 rear end probably.
Also, fox 36 150mm dimensions?
Thanks in advance!

Shimano makes finding there dimensional info pretty difficult, ??

here you go click me

shimano shared https://drive.google.com/file/d/1ETkhECjKR0BQVbmWuJfbjYJBT8sETSwq/view?usp=sharing

Posted: Feb 10, 2018 at 15:42 Quote
findhan wrote:
Hello guys, havent posted here in a long time: looking to make a single pivot frame to get back in the game and keep things simple. Im thinking of putting a Shimano 1x11 drivetrain on it (SRAM too pricey for prototypes!!) Probably M8000, 32 chainring, One of the areas I have struggled with in the past is getting the rear end chainstays sorted - so could anyone hit me up with some CAD models, 2D or 3D or even specs from Shimano on crank, chainring and hub dimensions or the likes? Is there anywhere where this is all in one place? 27.5 inch wheels with Boost 148 rear end probably.
Also, fox 36 150mm dimensions?
Thanks in advance!

You should be able to find all relevant dimensions of all Fox products here.

Cheers!

Posted: Feb 22, 2018 at 7:55 Quote
Tahsnk CompositePro and NickBosshard

Posted: Mar 2, 2018 at 21:51 Quote
Simple question, Bikecad Pro. worrth it?
I find the web app so frustrating that its hard to tell if the full version is worthwhile..
It seems alot of guys use it and its not particularly expensive.
anyone on here use it?

Posted: Mar 6, 2018 at 18:17 Quote
I don't personally have it, but a buddy of mine does and he loves it. What's the price? If it's not too expensive then you can't really go wrong. I'd say go for it! tup

Posted: Mar 7, 2018 at 1:16 Quote
200 usd or something


 
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