Bandit/GSXR Suspension Retrofit Questions

[mmattockx]

A couple questions I have not seen asked/answered before. Bike is my 82 1100E.

1) For the guys who have done either the Bandit or GSXR conversion, how did the handling change with the addition of wide 17" radials? Did it become more/less stable, how did turn in change?

2) Does anybody know what a set of early GSXR USD forks and triples or Bandit forks and triples weigh?


Thanks,
Mark

[posplayr]

https://www.thegsresources.com/_forum/showthread.php?135919-1st-Gen-GSXR-upgrade-for-GS1100ED&highlight=gs1100E+restromod

18" radials 170/60-18 and 110/80-18



1.) The bike remains heavy, there is nothing you can do about that. I'm pretty sure that the turn in changed but that is not what sticks in my mind as a comparison(not sure I can even remember how to describe any change) as the biggest factor on turn -in is having worn, squared off tires.

With my 1166 and OEM suspension (albeit upgraded with F springs, emulators, braces, Ohlins rear) the bike was somewhat unstable at about 60-70 mph.
Wit the GSXR 1st gen and 18" wheel, that unsteadiness was pushed much higher well over the ton.


I don't have any weights. Katman posted some at one point. The USD are definitely heavier than RSU GSXR. I doubt you would notice it though.

If you want to flick a bike, it would be better to find something smaller and lighter (like a 1st gen GSXR with 2dn gen suspension).

If you can keep the same ground clearance, I'm sure the 17" wheels would be even more stable than the 18". But without being on a track, you are not going to be using that new found grip.

[mmattockx]

With my 1166 and OEM suspension (albeit upgraded with F springs, emulators, braces, Ohlins rear) the bike was somewhat unstable at about 60-70 mph.
Wit the GSXR 1st gen and 18" wheel, that unsteadiness was pushed much higher well over the ton.

That's interesting as my 1100E also gets a bit of a wiggle sometimes at highway speeds. I also have upgraded the front end with springs and emulators and have IKON shocks that are almost 1" longer than stock.

I don't have any weights. Katman posted some at one point. The USD are definitely heavier than RSU GSXR. I doubt you would notice it though.

I'm not comparing the forks to other forks, I want to know what they weigh to see if a custom leading link fork can be made as light. I don't think I can get it that light, but without a target I will never know.

If you want to flick a bike, it would be better to find something smaller and lighter (like a 1st gen GSXR with 2dn gen suspension).

I agree. I am not trying for flickable in particular, just more interested in the changes that come with the 17" wheels. I see lots of comments from people who have done the switch but they seldom are specific about the results.


Mark

[posplayr]

Part of my rear wiggle problem was not having a stiff enough rear spring. Carrying a loaded of tents and travel gear made it worse. Increasing power made it even worse. I attribute most of it to rear wheel sidewall flex. the 170/60-18 on a 4.5"x18"has got a very short sidewall much like a 180/55-17 on a 5.5"x17". No doubt the 17" is stiffer than the 18", but for street riding it doesn't really show up.

[mmattockx]

Part of my rear wiggle problem was not having a stiff enough rear spring. Carrying a loaded of tents and travel gear made it worse.

Hmmm, that's different than mine. Mine goes away completely when I have a passenger. I figure the extra 1" of ride height at the rear is getting the steering steep enough to just give a bit of instability and adding a passenger sags the rear enough to flatten the bike out close to stock geometry.


Mark

[posplayr]

Hmmm, that's different than mine. Mine goes away completely when I have a passenger. I figure the extra 1" of ride height at the rear is getting the steering steep enough to just give a bit of instability and adding a passenger sags the rear enough to flatten the bike out close to stock geometry.


Mark

Part of the problem of getting an answer is that for example in my case so many things changed at the same time to make an assessment about a single thing. When I had the stock wheels I was using the cheap unadjustable Ohlins 13" and with a spring sprung for about 200 lbs.

When I went GSXR, I had the fully adjustable Ohlins (which is length adjustable to about 35mm) with a stiffer 220 lbs spring.

That said my whole odyssey of rebuilding by GS1100ED OEM and then GSXR was to explore how much of a difference each modification made. I did not do all combinations but rather pushed ttheOEM as far as it would go, then did a fairly aggressive 1st gen GSXR.

[posplayr]

I felt the Bandit Swingarm / 95 GSXR1100 fork combo were quite a bit more stable than OEM. No question radial tires make everything better, like bacon. I ran a 170 X 17 rear and 120 front. Converted the swingarm to twin shock. I would guess it's heavier as well.

Those are some of the longest USD GSXR forks, but ground clearance is still a concern. Walking speed when approaching speed bumps. The good thing is the USD forks have less travel.

If I were going to do it again for handling I would look for RSU with quality cartridges and longer length and I'd convert to mono shock and frame bracing. It still wouldn't be as good as post 2000 bikes.

With 18" wheels, 35mm shock extensions and 4:2:1 exhaust I did not have any ground clearance problems. I removed the lower braces from my engine guards (2 pointsmount), and would lift my toes as those were the things that would drag first.

I also had the bandit swinger which probably helped (according to Katman) but coupled with the rest of the suspension there is no way for me to distill the swingarm alone.

[Agemax]

i have a 91 GSXR1100 JMC swingarm and rear wheel in my GS1000, with Hagon shock. Front end is 1100 Katana forks with stock springs and deleted anti dive units. GS500e front wheel. 180/17 rear tyre and 120/17 front.
Handles very well and ride height remains good. whole bike weighs in at 220kg fully wet.
WP_20180521_11_37_43_Pro.jpg

[maicojoe]

Posplayr, do you have numbers for your bike for the following?
Rake, Trail, triples offset, top and bottom triple, fork length from top of tube to axle centerline, ground clearance for lowest piece like the exhaust, seat height, rear shock length center to center on the mounting bolt, available stroke or travel of forks and shocks, diameter of front and rear tires, degrees of steering lock to lock, distance of swing arm pivot center to average center of rear axle, distance from swing arm pivot to lower shock mount, and finally your average wheel base center of axle to center of axle. I would like to do a CAD drawing of your bike's dimensions to compare to my modified 1983 GS1100e with the 16" GS1150 wheel and front end, and to my stock dimension 1982 GS1100e.
Thanks, JN

[posplayr]

Posplayr, do you have numbers for your bike for the following?
Rake, Trail, triples offset, top and bottom triple, fork length from top of tube to axle centerline, ground clearance for lowest piece like the exhaust, seat height, rear shock length center to center on the mounting bolt, available stroke or travel of forks and shocks, diameter of front and rear tires, degrees of steering lock to lock, distance of swing arm pivot center to average center of rear axle, distance from swing arm pivot to lower shock mount, and finally your average wheel base center of axle to center of axle. I would like to do a CAD drawing of your bike's dimensions to compare to my modified 1983 GS1100e with the 16" GS1150 wheel and front end, and to my stock dimension 1982 GS1100e.
Thanks, JN

I have an excel spreadsheet that I used to configure the bike. I don’t have all the dimensions and the bike has been broken down. Pm me your email.

ps I know Johnkat worked on an extension to compute head tube angle as function of shock extension (IIRC). I wofken on it for a while but it got. Little complicated and I lost interest as my bike was already done.