Conversion to 17" wheels

[MKP]

Sorry if this has already been covered elsewhere. I am considering fitting 17" wheels to my 1200GS. I've seen plenty of threads relating to 1100/1150 but not 1200. If anyone has done it, was it easy, what has to be modified etc.

Many Thanks

 

[NorthernBoy]

Why the change?

 

[Yonkyo]

I did it, and you will all the info you need here:
http://www.ukgser.com/forums/showthread.php?t=84686&highlight=supermotarded

 

[MKP]

Thanks for the reply

 

[NorthernBoy]

Is it for performance reasons?

If so, I'd recommend trying the bike round a track before you make the change. I've just come back from the Nurburgring on the standard wheels (with Bridgestone BT020/021 combination on it), and had no problem running right up to the edge of the tread (to the point where it's got ragged rubber hanging off the surface's edges), as well as being faster around it than the majority of sportsbike riders.

It'd be a shame to go to the effort of making the change without having properly found out what the standard bike can do first.

 

[Yonkyo]

Northernboy
I ran my previous 12GS with 17" sports wheels and tyres.
But to be honest, the only advantages were:
1 A huge choice of Tyres.
2 much faster steering and with less effort required.
3 looked pretty trick.

However, disadvantages were:
1 initial cost of wheels.
2 sports Tyres don't last very long (2k miles from rear)
3 reduced ground clearance, with risk of the heads scraping.

I now have a GSA with ESA, and I prefer the way it handles as standard.

I'd love to do the Nurbergring on my HP2S though.

 

[NorthernBoy]

I'd love to do the Nurbergring on my HP2S though.

I can't recommend it highly enough. A friend of mine was going down on his ZX10, and asked if I wanted to join him, so I decided to give it a go. It turns out that most sessions are only evening ones, and these are sometimes only an hour and a half, but we still wanted to give it a try.

The trip down was fantastic, and the roads around the circuit were great, but there were really only the appetiser for the amazing 'Ring itself.

Riding past the new circuit, the grandstands, and into the car park for the Nordschleife had the hairs on the back of my neck standing up, and the nerves fraying, and seeing the track through the trees, with the painted armco, and grafitti lined tarmac did nothing to help.

I'd assumed that I'd be one of the slowest out there, with it being my first time, and with me being on a GS, but this was far from the case. My mate has a ZX10, and rides it very well (no other bike passed him all the time we wee there), but after two laps, he was not catching me before the 15km mark, having joined the track about 15 seconds after me each time.

Basically, the 'Ring rewards smoothness and high corner speeds more than aggression, and for this, the GS is excellent. The fact that it telegraphs how close to the edge you are means that you need to be a very good rider on another bike to be going much faster. We did not time ourselves (having decided that it was tempting fate to always be looking to gain seconds on every bend), but by the end of the second session, neither of us were being overtaken (by bikes), and both of us were passing plenty of superbikes each time out.

I'm already addicted, I think. I'm off to Brands this week to get some more practice in, and have been scouring Autotrader for an Exige to take back next time.

I'd really recommend doing it. It's only four hours ride from Calais, there are plenty of cheap guesthouses round about (most of which cater very well for bikers), and the thrill of riding that track is something that I think will live with me forever.

 

[Schtum]

You, both, might want to check out Ben Lovejoy's site.....

http://www.nurburgring.org.uk/

 

[NorthernBoy]

Thanks, I looked at that one before I left, and it was very helpful.

I'm left wondering what to go back in or on next time. Much as I loved the bike around there, it was clear that the cars were much, much faster. Even a normal road car was competitive with a fast bike, and the Porsche GT3s were just in a different league.

 

[Schtum]

Thanks, I looked at that one before I left, and it was very helpful.

I'm left wondering what to go back in or on next time. Much as I loved the bike around there, it was clear that the cars were much, much faster. Even a normal road car was competitive with a fast bike, and the Porsche GT3s were just in a different league.

Yes, I've been having impure thoughts about taking my wife's recently acquired BMW 123d over.

 

[Yonkyo]

Sounds like you werent hanging about on your GS.
Have you modified your GS? Pipe, PC Etc?

I haven't done a track day since I wrote off my ZX10R. Mind you, I think I could still
give few SB riders a shock on my GSA

You, both, might want to check out Ben Lovejoy's site.....
http://www.nurburgring.org.uk/

Thanks for that

 

[NorthernBoy]

Sounds like you werent hanging about on your GS.
Have you modified your GS? Pipe, PC Etc?

Completely stock, except for a pair of Bridgestone BT 020/021s. It did come as new with the Akrapovic pipe, but that's more about saving eight than gaining any power.

I was genuinely surprised at how I did. I've done a lot of track days on four wheels, and am normally near the top of the sheets when timing is involved, but on bike days I've never seemed to manage to get the best from other bikes. From sessions with Ron Haslam on an FZR600, through days on my 'Blade, it's never quite clicked before, and I've always found people on slower bikes passing me.

The combination of track, bike, and rider just seemed to work this time. It was the first time that I've ever had the pegs down on a bike except when I'm crashing, and it was all down to the confidence that the bike gives me. ABS and traction control being there helped, as I was happy to know that if I gave it a little bit too much beans, the bike could well help me to stay out of the barrier.

My mate on his ZX10 was faster, but only slightly, and made up for it by slamming into the barrier five laps in, and ending his trip liming home on a bungeed together machine.

I know that I seem to be raving a bit about the whole thing, but I learned more about the bike there than I have in the last couple of years of road riding, and came away truly gobsmacked by how much fun you can have. That it was only about a month ago that I had the bike offroad over Mont Blanc really leaves me amazed at how capable the GS is.

 

[NorthernBoy]

Yes, I've been having impure thoughts about taking my wife's recently acquired BMW 123d over.

I think that my car would go pretty nicely around there (RS4), but hesitate to take it, given that the cost in tyres, clutch and sundry other bits woudl probably add up to much more than the cost of hiring something more appropriate.

Which, of course, makes me wonder why on earth I am running an RS4 at all...

 

[patzx12]

Not really true, I have done the conversion, the heads have more road clearance with a smaller front wheel. Strange but true if you think about it.

Northernboy
I ran my previous 12GS with 17" sports wheels and tyres.
But to be honest, the only advantages were:
1 A huge choice of Tyres.
2 much faster steering and with less effort required.
3 looked pretty trick.

However, disadvantages were:
1 initial cost of wheels.
2 sports Tyres don't last very long (2k miles from rear)
3 reduced ground clearance, with risk of the heads scraping.

I now have a GSA with ESA, and I prefer the way it handles as standard.

I'd love to do the Nurbergring on my HP2S though.

 

[NorthernBoy]

Not really true, I have done the conversion, the heads have more road clearance with a smaller front wheel. Strange but true if you think about it.

Nope, I've thought about it, but it still definitely seems that putting a smaller front wheel on is going to make the cylinder heads deck out earlier.

How are you looking at it to imagine it being otherwise?

 

[Yonkyo]

Not really true, I have done the conversion, the heads have more road clearance with a smaller front wheel. Strange but true if you think about it.

do the math
A GS with 17” wheels with a 120/70/17 front and 190/50/17 rear tyres
= 35mm lower front and 20mm lower rear as opposed to a standard 19” F (110/80/19) – 17” R (150/70/17).
= almost 35mm less ground clearance with a 17” front wheel.
No wonder I was dragging my centre stand and foot pegs when cornering.

Here she is

 

[NorthernBoy]

Given that it is not so hard to drag the pegs on the standard wheels, I'd be pretty worried about how compromised it was going to be by dropping it at all, let alone by nearly two inches at the front.

 

[patzx12]

Certainly ground clearance is reduced but it wouldnt be possible to grind the heads with 17" wheels, you would have to grind out the footpegs, stands ect.
The ratio between pegs and head in relation to the road has increased.
You could grind the head with standard wheels and the suspension on its top setting.The pegs act as a good angle of dangle indicator. The steel pegs are nice and loud, they are saying "hang off more or get an R1"
See the before and after pics.