17 inch Conversions

stick · Apr 1, 2020

Anyone know a way or an off the shelf system for the conversion that will stop the offset caused by the fitment of the wheels, I ask as this would do my head in to have the offset and put together with the steering angle change this would possibly make a bike unstable at speed and also hard cornering.
I have read that the trade off for the sportier tyres is the possibility of high speed instability and as above mixed with an offset may not be good.
Any ideas as im a bit bored and may give it a go.( still working but not spending if you see what I mean)
The reading was an article on this site.
https://www.ukgser.com/technical/ni...moto (BMW R1200GS & GSA, '04 to '13) V1.0.pdf

Arsey · Apr 1, 2020

PAGING BOXERLUST.......

stick · Apr 1, 2020

No No No No No ….. im board not suicidal FFS

Winjar · Apr 1, 2020

There is a company in Germany do this I cannot think of name.

stick · Apr 1, 2020

I think is Reh something but they do not mention the off set issue , thanks for the reply tho

Skid06 · Apr 1, 2020

Several options, the off-set does upset the handling a little and looks very obvious from behind even though its only 12mm, RT-RS Wheel and Machine the Hub, or use the RS swinger, or use the 1300s Wheel as i've done and fit a 190 Rear no machining

Skid06 · Apr 1, 2020

Tyre fits a treat in standard swinger

Skid06 · Apr 1, 2020

side view just ordered a set of super corse tyres

Spareparts · Apr 1, 2020

Extra weight on the rear and slower turning. Why?

stick · Apr 2, 2020

stick said:
I think is Reh something but they do not mention the off set issue , thanks for the reply tho

Spareparts said:
Extra weight on the rear and slower turning. Why?

Can you explain more , or do you mean more contact rear thus slower at the front ? Thanks

stick · Apr 2, 2020

skid06 said:
Several options, the off-set does upset the handling a little and looks very obvious from behind even though its only 12mm, RT-RS Wheel and Machine the Hub, or use the RS swinger, or use the 1300s Wheel as i've done and fit a 190 Rear no machining

Thanks for the pics and the info , is it a right fit with the 190 or can you go for a 180 on the k wheels , also does the front K fit straight in . Cheers

r1happy · Apr 2, 2020

skid06 said:
Several options, the off-set does upset the handling a little and looks very obvious from behind even though its only 12mm, RT-RS Wheel and Machine the Hub, or use the RS swinger, or use the 1300s Wheel as i've done and fit a 190 Rear no machining

Thanks Skid for your update which is very useful for me. I have had RS front & rears fitted since bike was new last March, and the handling has been fine but looks weird from the back. I have acquired an RS swinger which is yet to be fitted, however by coincidence I just got a 1300S rear 2 days ago!

From your comments I think I will hold off fitting the swinger and just go with the bigger wheel. Just had Metzeler M9rr’s fitted but not ridden yet, so will get a 190/50 M9 as soon as the dealers open.

Spareparts · Apr 2, 2020

stick said:
Can you explain more , or do you mean more contact rear thus slower at the front ? Thanks

Slower at the rear. A 190 tyre generally has a flatter tyre profile than a 170 with a larger cross-sectional radius. Unsprung weight and rotational mass is significantly higher too, increasing gyroscopic forces and therefore reluctance to tilt off the centreline axis. Yes a 190 can offer larger contact when leant over, but the GS does not need more lateral grip when it is a slow vmax machine. There are no advantages other than perhaps looks.

stick · Apr 2, 2020

Spareparts said:
Slower at the rear. A 190 tyre generally has a flatter tyre profile than a 170 with a larger cross-sectional radius. Unsprung weight and rotational mass is significantly higher too, increasing gyroscopic forces and therefore reluctance to tilt off the centreline axis. Yes a 190 can offer larger contact when leant over, but the GS does not need more lateral grip when it is a slow vmax machine. There are no advantages other than perhaps looks.

I would not call it slow to be honest as you can push hard on the Gs , unless on the track , I had wondered if it slowed the bike but with a 17 on the front this should balance up the bike . The CTA3 has a broad rear and a shrp front , the front makes the bike drop in even tho the rear is wider than say a PR5 rear.

r1happy · Apr 2, 2020

After Skids update I tried the 1300 wheel on my bike.

It’s more central than the RT wheel I have on at the moment, but it is still offset. I have taken some pics to show/compare.

I then ran a plumb line off the back in line with the centre of the rear light and painted a mark on the centre of the 1300 wheel to show.

Spareparts · Apr 2, 2020

stick said:
I would not call it slow to be honest as you can push hard on the Gs , unless on the track , I had wondered if it slowed the bike but with a 17 on the front this should balance up the bike . The CTA3 has a broad rear and a shrp front , the front makes the bike drop in even tho the rear is wider than say a PR5 rear.

One of the reasons why I have not been impressed by Continental tyres - although I have yet to try the CTA3. The flat profile of the rear makes the bike feel slow to get on its ear. Tyre profile is one of the most important things to me in affecting the handling of a bike, and a flat profile tyre is rarely advantageous (unless riding in a straight line). A 190 tyre is not necessarily optimal for a flickable/nimble bike either - a number of supersport (600-900cc) sportsbikes often cam with only 180 section rear tyres in recognition of the importance of flickability - and most of those supersport bikes are capable of far high lateral speeds than a GS could ever muster. So I would be very cautious before before moving to a 190 tyre on a GS... I just see no net-benefit given the GS' performance, especially if you value performance and handling.

Edited to add> the PR5 has an exceptionally high degree of lateral grip because of its very steep profile if that is what you are looking for: pointy, then wham on its side where the contact patch is large - even for a 170. Not very feelsome (less so than a PST2), but grippy.

Skid06 · Apr 2, 2020

The benefit is using it with a 17" Front Wheel along with decent suspension (ohlins ttx) makes it great fun
R1Happy: my rear wheel from a 1300s looks dead center with no offset, i did have the RT Wheel but couldnt get on with the offset

Skid06 · Apr 2, 2020

Spareparts said:
Extra weight on the rear and slower turning. Why?

Id say its a tad lighter
it turns like lightning (with the 17" front)

(i do have a few nice sports bikes as a reference)

Reggie353 · Apr 4, 2020

The company was called Rennkuh. Can’t find his website now.

Sent from my iPhone using Tapatalk

walkingpictures · Apr 4, 2020

www.rennkuh.de as far as google knows!! Currently offline apparently

17 inch Conversions

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