2000 GSXR 750 vs SV

Originally Posted by northwind

It's quite a lot of work to get it that light... Though most of it came by accident, lighter exhaust etc- total weight wasn't ever the goal til recently. Oh, it still has the steel rear subframe, for carrying luggage It wouldn't be worth it in its own right, ie if I'd just set out to lighten it, I'd be disappointed by the results. But it's still nicer to ride IMO, and it comes without sacrifices. I need to ride another stock SV to really compare though. Once the rear dymag's in it'll drop below 170, but now it's going to get difficult.

i read somewhere that dymags arent really any lighter, they just have better weight distribution or somthing?? any truth in this?

[yorkie_chris]

With a wheel it's moment of inertia which matters ... decides on gyroscopic forces which affects ease of turning and stability

[yorkie_chris]

So that 125kg cagiva planet in the garage could be a right laugh with a 70bhp powervalve motor in it...

Originally Posted by northwind

It's quite a lot of work to get it that light... Though most of it came by accident, lighter exhaust etc- total weight wasn't ever the goal til recently. Oh, it still has the steel rear subframe, for carrying luggage It wouldn't be worth it in its own right, ie if I'd just set out to lighten it, I'd be disappointed by the results. But it's still nicer to ride IMO, and it comes without sacrifices. I need to ride another stock SV to really compare though. Once the rear dymag's in it'll drop below 170, but now it's going to get difficult.

Aye... The weight I quoted was with stock Zorsts... I think. Was a guy on the prila site who weighed one in. Considering the stock zorsts weigh a tonne liturally drop a fair few KG's through losing those. I might get the Oz wheels, I think that loses about 8 KG for both wheels changing!!!

Originally Posted by pencil shavings

i read somewhere that dymags arent really any lighter, they just have better weight distribution or somthing?? any truth in this?

Couldnt be sure but I would suspect they are lighter...

[northwind]

Originally Posted by pencil shavings

i read somewhere that dymags arent really any lighter, they just have better weight distribution or somthing?? any truth in this?

I think that was PB if memory serves. Or it might have been me It's true, some production wheels are lighter than my mags, ZX6R I think with the 6 spokes is lighter. But, like YC says it's all about where you carry it. The ZX wheel has a really strong rim so it can get away with light spokes and hub, and overall that makes it light on a scale- but the weight is right out at the rim, in the worst place. my dymags- they're the 3 spoke type- have very strong spokes which brace a lot of the rim's circumference, so the rim can be a lot weaker and lighter- so even though the mag's slightly heavier than the OEM, it acts as though it's lighter. Insert patronising analogy with ladders and weights here

Funnily enough, the multi-spoke aluminium marchesinis on Ducatis are actually ridiculously heavy They just look light. Bandit 12 wheel is lighter than a 749 wheel, if I remember my numbers right.

With the wheels I've used- SV, Bandit and GSXR- the Dymags are a fair bit lighter. My entire 5.5 inch rear wheel and 180 tyre is something like 1.5 kilos lighter than the SV 4.5 inch rear wheel with a 160 tyre, comparing like with like.

very interesting.

The weight thing has opened up a whole new area of knowledge that I didnt have much insight into.

my limited knowledge told me that the lower the unsprung weight the better... but i guess this isnt the case if it is better distributed? I guess there would become a cut off point thought, where regardless of how well it is distributed, a lighter wheel would be better...

Originally Posted by pencil shavings

my limited knowledge told me that the lower the unsprung weight the better... but i guess this isnt the case if it is better distributed? I guess there would become a cut off point thought, where regardless of how well it is distributed, a lighter wheel would be better...

I agree that would be the case! TBH though for the road there comes a point where its just major over kill... But then that doesnt matter if you have money to waste Shame I dont

[northwind]

Yeah, I'm just not fast enough to get the full benefit of the dymags, that's for sure. Anyone can benefit from a lighter bike, it's just plain easier to ride (and easier to push, and to pull out of a ditch!) but to really make the most of it is a different story.

(mine is all done on the cheap- frinstance front dymag was £120, I sold the SRAD wheel for £75... rear Dymag was in a pair for £250, I sold the front one for £200 They're both unfashionable fitments- ancient Fireblade and fairly ancient CBR- so not in high demand. And angle grinder discs are cheap )
BUT! Buying used magnesium wheels is a gamble and a half. One of mine was off a show bike, the others were in beautiful condition but you still never know.

[yorkie_chris]

I'm not convinced the ultralight wheels are a good idea on the road.

[northwind]

They'd be easier to bend, that's for sure... But I've had the front one on for 10000 miles or so and it's fine so far. I'm always careful with kerbs, mind.