Rear suspension frame



Dr Gonzo

Member
Joined
Mar 29, 2018
Messages
45
Lol. Yeah but the design looks like something I could mimic or improve on with a custom frame. I'm just wondering if anyone has used these in the past and how the suspension worked out for them.
 

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,674
Lol. Yeah but the design looks like something I could mimic or improve on with a custom frame. I'm just wondering if anyone has used these in the past and how the suspension worked out for them.
Yes some members have used them. I'm not sure if they used them as trail bikes though, since the Coupe Deluxe is notorious for the damping blowing out even when it's just used as intended.
With the damping gone, the spring rate will be far too weak.
You might be able to fit a modern air shock into the space, although not many would be small enough.
Occasionally Coupe Deluxe shocks do appear on the auction site, but I wouldn't count on being able to keep replacing the blown shocks forever.

Also, I have no idea how long the old aluminium frame would last. For customising, it might be better to start with a cro-moly frame (LTS 5 or 5000).
I have a GT LTS 5 which is a cro-moly frame, and I have an ambition to customise that. In it's stock form it's pretty awful, having only a springer rear, no shock, but I have a decent old Fox shock from the Specialized Big Hit so I just need to lengthen the chainstays and fabricate a new top link whatsit to fit the comparatively huge shock.
 

Dr Gonzo

Member
Joined
Mar 29, 2018
Messages
45
nice. i didn't even consider the lack of lasting power the springs would have. lol. noooooob liiiife!! i guess i should've since ive read that front air suspensions are better than springer shocks because springers get wobbly at high speeds and turns.
 

panmines

Active Member
Joined
May 28, 2015
Messages
113
Its worth mentioning the GT LTS is one of the very few frames that allow for both rear suspension and a jackshaft. If you want a trail bike, this is the ideal frame.
fppe1.JPG
 

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,674
nice. i didn't even consider the lack of lasting power the springs would have. lol. noooooob liiiife!! i guess i should've since ive read that front air suspensions are better than springer shocks because springers get wobbly at high speeds and turns.
It isn't the spring that doesn't last, it's the oil damping, the seals blew out. In the late 90's the downhill mountain bike scene was progressing and the new alpine style tracks that actually had properly rough rocky ground instead of just being a path laid out in sloping grassy field. Even for non-racing use the little Coupe Deluxe shocks couldn't keep up with what people wanted to do and were blowing out their seals.
The spring rate is weak because the spring is supposed to be supported by the damping, so once the damping blows up you're left sitting on the bottom bumper. It was the common fate of these bikes.
Nowadays retro MTB enthusiasts still ride old LTS frames but really only for cruising around the streets. I should think it's fine for doing the same thing motorised; but you said you wanted opinions on it as a trail bike, and a motorised trail bike should be able to handle some rough ground at motorised speeds and with the added weight, without worrying about it and having to baby it.
The answer is a slightly more modern, much larger shock, for which you need to redesign the frame. So I am in favour of the LTS as a base for a custom build, but I think the cro-moly ones are probably a better idea, and they happen to be the cheapest ones too, because they were always the bottom of the LTS range. :)
 

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,674
Its worth mentioning the GT LTS is one of the very few frames that allow for both rear suspension and a jackshaft. If you want a trail bike, this is the ideal frame.
View attachment 81353
That looks like a nice LTS 4000 frame. :) Cro-moly frame. :) Only the LTS 5 and LTS 5000 are cro-moly.. and a quick edit, apparently the 4000 is cro-moly and that's what this green bike is.

I think it would work with or without the SBP Shift Kit, tbh, as the linkages in the chainstays help to keep the chain length fairly even throughout the travel.

The Rockshox (Indy?) front and Rockshox Coupe Deluxe rear suspension on this bike are wholly inadequate for any serious riding though. The fork is easily upgraded but the rear shock is a bit more tricky, it would take some fabrication.
 
Last edited:

panmines

Active Member
Joined
May 28, 2015
Messages
113
That looks like a nice LTS 5000 frame. :) Cro-moly frame. :) Only the LTS 5 and LTS 5000 are cro-moly.

I think it would work with or without the SBP Shift Kit, tbh, as the linkages in the chainstays help to keep the chain length fairly even throughout the travel.

The Rockshox (Indy?) front and Rockshox Coupe Deluxe rear suspension on this bike are wholly inadequate for any serious riding though. The fork is easily upgraded but the rear shock is a bit more tricky, it would take some fabrication.
Yeah, I don't know this bike so well and wouldn't be able to tell the difference between the two. My point was this is the only bike frame that I know of that allows for both rear suspension and a jackshaft. Of course you could run a direct drive If you wanted to. Any other rear suspension bike has a shock inside the frame and blocks the positioning of a motor.
 
Top