R100GS forks into R80ST or G/S

[scooter paul]

Fitting R100 GS forks from a paralever model into a ST or G/S frame is relatively straightforward. The steering stem, tapered bearings are the same. The steering stops all line up. I wanted to use my R80G/S wheel and found that drawings exist on the interweb for a custom front axle that fits the larger diameter of the lower fork legs but matches the smaller bearing size of the older wheel. Suitable spacers are included in the drawings though I found out that they are shown the wrong way round.
I’ve used a standard R100GS front calliper as the ST one is fitted to the rear of the leg not the front on the new forks.
I had already used Magura off road master cylinder and a custom hose from Venhill which was just long enough.
Here are some pics. I haven’t ridden it yet but the look is much more purposeful and just what I was looking for.

 

[Tbolt]

Good to see this completed.

If the GS forks are longer are you using the centre stand from a G/S or ST?

If it is from a G/S does this make it easier to lift on to the stand.

 

[scooter paul]

Good to see this completed.

If the GS forks are longer are you using the centre stand from a G/S or ST?

If it is from a G/S does this make it easier to lift on to the stand.

I’m using the ST stand but I’d already made it longer ( and repaired the ‘feet’) when I fitted the G/S length rear shock. It’s always been easy to lift on the stand and the longer forks still allow the front wheel ( or back) to spin freely when lifted.

 

[Tbolt]

Thanks, I have a ST stand to put on my G/S. Much easier to use. Just need to get the springs right.

 

[scooter paul]

Thanks, I have a ST stand to put on my G/S. Much easier to use. Just need to get the springs right.

If you ever need a complete set of ST forks you know where to ask!!

 

[Tbolt]

Cheers.

Can you send me a link for the GS spindle.

I have some GS forks to consider fitting.


Sent from my iPhone using Tapatalk

 

[scooter paul]

In image 1 bushes 3 and 2 should be transposed. In other words bush 3 should be to the left of the image, right hand fork side.

 

[scooter paul]

For Bush 2 use drawing for Bush 3 but 16.5 mm not 18.3

 

[Tbolt]

For Bush 2 use drawing for Bush 3 but 16.5 mm not 18.3

Thanks again.

 

[sidkn33]

Fitting R100 GS forks from a paralever model into a ST or G/S frame is relatively straightforward. The steering stem, tapered bearings are the same. The steering stops all line up. I wanted to use my R80G/S wheel and found that drawings exist on the interweb for a custom front axle that fits the larger diameter of the lower fork legs but matches the smaller bearing size of the older wheel. Suitable spacers are included in the drawings though I found out that they are shown the wrong way round.
I’ve used a standard R100GS front calliper as the ST one is fitted to the rear of the leg not the front on the new forks.
I had already used Magura off road master cylinder and a custom hose from Venhill which was just long enough.
Here are some pics. I haven’t ridden it yet but the look is much more purposeful and just what I was looking for.

Hi Paul, I'm looking to upgrade my ST in the same way, using the original 19" wheel.
What is the source of the custom axle drawings and where did you source your axle and spacers from?

Thanks in advance.

 

[scooter paul]

Hi Paul, I'm looking to upgrade my ST in the same way, using the original 19" wheel.
What is the source of the custom axle drawings and where did you source your axle and spacers from?

Thanks in advance.

Please send me your email address by personal message and I’ll mail the drawings. I gave them to a pal who uses an engineering firm locally to machine them up.

 

[sidkn33]

Please send me your email address by personal message and I’ll mail the drawings. I gave them to a pal who uses an engineering firm locally to machine them up.

Sending now - much appreciated

 

[bmwshtone]

Could I get those detailed plans as well, please?

 

[scooter paul]

Could I get those detailed plans as well, please?

Message me with your email address and I’ll send them off.

 

[scooter paul]

Message me with your email address and I’ll send them off.

In fact if you scroll back to May 2022 they are all there plus some notes I added.

 

[sidkn33]

I've finally fitted my GS forks and ST 19" wheel , having had a custom axle made to the specs supplied here by @scooter paul (thanks very much Paul!)

I also used an R1150 caliper (as I have on my 1992 R80GS PD) with a custom made 285mm disc for better braking
The original ST disc is 260mm and too small to work with the new GS forks and R1150 caliper combination, hence the custom 280mm disc which was actually only a tad more expensive than a new standard disc.
All Bike Engineering supplied the disc.

I'm struggling to embed a photo - only option appears to be via URL, but UKGSER won't accept a Google photos URL.
So just plain old link will have to do.
https://photos.app.goo.gl/VFkgAwCjW7eDET948

 

[sidkn33]

I've finally fitted my GS forks and ST 19" wheel , having had a custom axle made to the specs supplied here by @scooter paul (thanks very much Paul!)

I also used an R1150 caliper (as I have on my 1992 R80GS PD) with a custom made 285mm disc for better braking
The original ST disc is 260mm and too small to work with the new GS forks and R1150 caliper combination, hence the custom 280mm disc which was actually only a tad more expensive than a new standard disc.
All Bike Engineering supplied the disc.

I'm struggling to embed a photo - only option appears to be via URL, but UKGSER won't accept a Google photos URL.
So just plain old link will have to do.
https://photos.app.goo.gl/VFkgAwCjW7eDET948

Just to add that I was running the R80ST with a GS 21" wheel on the GS forks previously, it was fine but having the 19" wheel reminds me how/why the ST is celebrated for its road-manners vs the G/S and GS.
The 19" front makes for a really planted, quick turning ride - it's great and also looks age appropriate for a 1983 bike!

 

[hypnofonic]

Hi am trying to do the same exact thing on my G/S. I have a full R100GS fork setup but dont have the wheel and glad to read that I can use my G/S wheel. Can one of you send me the specs for the spacers? Thank you so much!!

NOTE: I just read the whole thread and saw the pics of the spacers.. thank you!!

Cheers for CA!
Andy

 

[sidkn33]

I'm still running my ST with GS forks and its original 19" wheel using ScooterPaul's diagrammed custom axle specs.
It works a treat.

 

[hypnofonic]

I'm still running my ST with GS forks and its original 19" wheel using ScooterPaul's diagrammed custom axle specs.
It works a treat.

perfect, was going to see if I can get it made.. I did not want to try to find a R100GS front wheel and glad to reuse my G/S 21" front. did you use stainless?