Rear suspension questions

Shop deals on ebay
Advertise with us
Find deals on amazon
Mini Dirt Bikes & Pit Bikes Forum

Help Support Mini Dirt Bikes & Pit Bikes Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
S

stoozo

Banned Wanker of the Century
Joined
Feb 21, 2014
Messages
2,144
Reaction score
12
Location
South Australia
So I pulled the shock out of my PitPro today. Its completely knackered. I was wondering if anyone has used a shock with a longer stroke in it something like this? 11" KLX 110 DRZ Rear Shock KLX110 DRZ110 PIT Bike SK12 | eBay

So the standard PitPro shock is 280mm with a 59mm or 60mm stroke(travel)

So that above fast ace shock is upping the stroke by about 10mm which would equate to a little more rear suspension travel. It shouldn't have to much impact on the swingarm geometry and the chain tension if its just going a little bit further. The gap seems to line up with the maths too. 280mm-70mm(full compression)= a little larger what is needed before the back wheel would hit the muffler.

I figure increasing the stroke is a good way to increase the rear travel but maintain the geometry how it is currently. I could go for a 290 or something and that would give me a little extra height on the seat. But I think it will mess with the geometry a bit. Also I cant seem to find 290mm rear shocks with long strokes like 70mm+ kind of territory. Sometimes I wonder if I'm jsut not looking in the right place. However I'm finding it frustrating as MANY of the shops dont list stroke length....which is kind of a big deal with rear suspension and getting the right shock for your bike!
 
Yeah see I've looked through most of those and they're all short stroke once again.

That has 63mm stroke DNM MTG RC 280mm 1000lbs IN Rear Shock | eBay

I'd get in the range of another 0.5-1 of rear travel. With the that shock that has 70mm stroke I should get another 2-2.5 inches of rear travel. I'm thinking I should be able to swap the spring from the busted shock or source a 1000lb spring from else where. Basically thats the shock that will make it really nice to jump due to the extra rear travel if only I could find one with a 1000lb spring ;) I found a couple that are 79mm stroke and 280mm but I think they I'd be getting into the territory of having to move the muffler so it wont hit the back wheel. That would be pretty awesome though 79mm stroke would up the rear travel to over 3inches on top of stock. I think I might be hitting slighly unknown territory with this stuff but we used to do it all the time on the DH bikes early on, before the factories figured out how to give you decent amounts of rear travel! :thumbup:
 
Last edited:
sounds like you are only working out the travel of the shock though ?
the point that the swingarm pivots on is forward another 4" - 5" from the bottom shock mount
the swingarm is 400mm from the front pivot point to the rear axle, and the shock mount is 100mm from the front pivot point.
here's an example, using your PitPro 60mm travel rear shock
if the rear suspension is compressed half way, the bottom of the shock will travel 30mm up,
but the rear axle (being 300mm further from the swingarms front pivot point) moves up 150mm
so you have a rear suspension travel of 300mm's

generally motorcycles are designed to be able to scrub the rear tyre on the underside of the fender when bottomed out.
adding 10mm more stroke to the shock will still have the tyre bottom out at the same amount of travel
 
you will need a slightly larger shock to compensate for the longer forks, unless your thinking of sliding them down in the triple clamps.

i would go a 290, or 300mm shock. you dont want to much further at all. what i suggest is cutting a bit of wood 300mm eye to eye, and see how the swingarm pivot looks, if its too raked, go to 290, and so on
 
the dnm is 290 eye to eye im pretty sure and it has a 850lbs spring. should be pretty well spot on for you by the time you do your preload etc. by the way pm me your address so i can post em tomorrow ;).
 
my67xr said:
sounds like you are only working out the travel of the shock though ?
the point that the swingarm pivots on is forward another 4" - 5" from the bottom shock mount
the swingarm is 400mm from the front pivot point to the rear axle, and the shock mount is 100mm from the front pivot point.
here's an example, using your PitPro 60mm travel rear shock
if the rear suspension is compressed half way, the bottom of the shock will travel 30mm up,
but the rear axle (being 300mm further from the swingarms front pivot point) moves up 150mm
so you have a rear suspension travel of 300mm's

generally motorcycles are designed to be able to scrub the rear tyre on the underside of the fender when bottomed out.
adding 10mm more stroke to the shock will still have the tyre bottom out at the same amount of travel
Click to expand...

Yes I get that bit after taking the shock out the pit pro on 60mm stroke as I measured it at the shock out back wheel sitting on the muffler the 280mm shock with a stroke of 60mm at full compression the suspension set up like that wont hit even hit the pipe which is under the rear of the frame....Which is why I think I can gain travel on at the rear wheel by increasing the stroke of the shock by 10mm...that should be scrubbing the underneath of the rear mud guard then!

gottagetacheaperhobby said:
dnm is 290 eye to eye im pretty sure and it has a 850lbs spring. should be pretty well spot on for you by the time you do your preload etc. by the way pm me your address so i can post em tomorrow[QUOTE/]

Yeah thats awesome should be about right! I'm just trying to work things out in my head in terms of getting it to scrub the underneath of the mudguard after realising it was miles off after I took the shock out!! Been a little unwell today, havn't been sleeping to well the last few night. I'm trying to swap the TDR to a guy with a Pitpro that has a yx160 in it...he says he just wants a new bike! See how that one goes...that would be a good deal!!
Click to expand...
 
my67xr said:
sounds like you are only working out the travel of the shock though ?
the point that the swingarm pivots on is forward another 4" - 5" from the bottom shock mount
the swingarm is 400mm from the front pivot point to the rear axle, and the shock mount is 100mm from the front pivot point.
here's an example, using your PitPro 60mm travel rear shock
if the rear suspension is compressed half way, the bottom of the shock will travel 30mm up,
but the rear axle (being 300mm further from the swingarms front pivot point) moves up 150mm
so you have a rear suspension travel of 300mm's

generally motorcycles are designed to be able to scrub the rear tyre on the underside of the fender when bottomed out.
adding 10mm more stroke to the shock will still have the tyre bottom out at the same amount of travel
Click to expand...

Yes I get that bit after taking the shock out the pit pro on 60mm stroke as I measured it at the shock out back wheel sitting on the muffler the 280mm shock with a stroke of 60mm at full compression the suspension set up like that wont hit even hit the pipe which is under the rear of the frame....Which is why I think I can gain travel on at the rear wheel by increasing the stroke of the shock by 10mm...that should be scrubbing the underneath of the rear mud guard then!

gottagetacheaperhobby said:
the dnm is 290 eye to eye im pretty sure and it has a 850lbs spring. should be pretty well spot on for you by the time you do your preload etc. by the way pm me your address so i can post em tomorrow ;).
Click to expand...

Yeah thats awesome should be about right! I'm just trying to work things out in my head in terms of getting it to scrub the underneath of the mudguard after realising it was miles off after I took the shock out!! Been a little unwell today, havn't been sleeping to well the last few night. I'm trying to swap the TDR to a guy with a Pitpro that has a yx160 in it...he says he just wants a new bike! See how that one goes...that would be a good deal!!
 
Just measured it so its 225mm eye to eye once the rear wheel hits the muffler at the shock end, and another 5mm to go so the wheel will scrub under the mudguard about right. So longer shock at 290 and more stroke about 63mm instead of 59 or 60 should work out about right! Cool solved no worries! Craig is right as usual and so is Tassy Stu....got to ask question to learn! Not I'm going to have to do something about the muffler getting destroyed by the back tyre...why did I buy a dunlop tyre that is really wide :thumbdown: but it was apparently the same size as the one that came off....

This is the real issue now i guess, DSC_0243.jpg

DSC_0242.jpg
 
Last edited:
You must log in or register to reply here.

Latest posts

Back
Top