Rear tyre too wide for SV?

The SV rear wheel is quite heavy.
Do you think switching to a lighter/thinner 140 rim and tyre is a good idea.
The steering would benefit as well.
Sometimes I think that the SV was given a 160 rear just to look good.
What's your opinion on this guys?

p.s. I'd like my SV to be a 140kg machine

[jambo]

I reckon the 160's quite well suited to the bike, but it's an interesting thought as most people go the other way.... 150 section tyre was standard on the Bandit 600 (early ones like I had anyway) and that was just fine. I doubt you'd get any weight saving at all going to that wheel and tyre though. The weight saving will have to come from the wheel itself, got any thoughts on a donor bike?

The "correct" way to go to save weight is to get a nice Dymag wheel on the rear.... But that's not a cheap option....

I'd reckon most of the bikes that take a 140 rear are pretty old now as it hasn't been sexy for a long time. The donor wheels might, therefore be heavier than the one on the SV due to improvements in manufacturing.....


But then, if I'm honest I know jack-all about this sort of thing....

Jambo

Originally Posted by zunkus

The SV rear wheel is quite heavy.

Blimey! Everytime my SV's rear wheel is out I think how light it is - compared to spoked wheels as all my other bikes have.

Have you ever had to remove the rear chazzyb? I'm telling you if you had a lighter wheel there a lot of weight saving could be done. Some guys are telling me that the stock forks are quite heavy as well. They're saying the Gixxer forks are half the weight and these are upsidedowners. Quite interesting when I thought that the upside down items should be heavier just by looking at them. The dymag wheel change is an option I suppose but not many people are willing to pay that much. If you look atb grey import 400cc inline 4's they mostly run on 140's and are quite capable of having a good contact patch and all that as most can keep up with theSV twin no prob. That's why I'm thinking the 140 rear section could be a good cheap option for a lighter bike. And if you ever had the chance to ride a light bike you'd know of the benefits that can be got.

[northwind]

The rear wheel's pretty heavy, definately... I'm still messing about with a CBR900 fitment Dymag rear, it saves, oh, lots. Don't know exactly how much tbh. Is there good availability for such relatively narrow tyres? Or wheels for that matter?

Dymags should save 1-1.5kg for each wheel. However the tyres themselves are a huge source of weight. The difference between different brands of tyre can be up to 1kg per wheel! That's the same benefit as a set of dymags just by choosing different tyres. Worth looking into if you can find a friendly tyre shop to weigh a few sets for you.

That's a good question Northwind. To be honest the idea of a narrower tyre germinated in the dark corners of me mind when I read reports from supermono racers of advantages in having narrower tyres for a given amount of bhp. It seems like wider tyres on production motorcycles are more of a fasion statement in most cases. In the case of the SV with 'only' 70-80bhp; which is quite enough power honestly for most of us, if used fully and reliably; a 150 section would actually have been a better fitment. These 150 section are used and available for supermono racers. Quite a lot can be learned from these light machines. I'm starting to see the sense in their thinking. Google supermono out and see what I mean.

A good exercise, for anyone with the means of having a breaker friend, is to check out the weight of varied 140/150 section rims and see if there is a real weight difference from which we may benefit. If there's a substancial amount maybe we could pursue the idea further. Apart from having gixxer forks and a light exhaust to lighten the SV I can't think of anything other that can reduce its weight by a noticeable amount. The rear aluminium subframe difference to stock isn't that much is it?

"Dymags should save 1-1.5kg for each wheel. However the tyres themselves are a huge source of weight. The difference between different brands of tyre can be up to 1kg per wheel!"
Quite right, so imagine having a narrower tyre, less material, less weight.

The subframe can make quite a difference depending on how minimalist you go. If all your after is a seat perch then yes it can. If your keeping the road trim then the frame has to be much larger and thus the savings will be less.

[northwind]

Originally Posted by tranx

Dymags should save 1-1.5kg for each wheel.

It's going to be a bit more than that I reckon, just by dead reckoning... I think it was 1.4 from the front going from GSXR wheel to Dymag, but the GSXR wheel in turn is lighter than the SV. Unfortunately I didn't keep very good records The SV rear is like an anchor though. If I get out to the garage this weekend I'll do some weighing.

Thanks Northwind the data would be nice. Did you ever find a domestic way to weigh the bike? Nice wheels those Dymags by the way! Stuff of dreams.