I'm devastated - sprocket/chain issues

thats a nice looking setup you have there....

arobsum wrote:

thats a nice looking setup you have there....

Yea, looks great - doesn't work!! Hopefully I'll get it working without screwing it up too much. Thanks

What wheel are you using and are you absolutely sure it's centred?

I'm using a 6" Hayabusa wheel with a 180 Racetec Metzeler tyre and a 10mm offset front sprocket with a 530 o-ring chain and it clears the tyre by about 3-4mm. I had to machine the sprocket carrier down by 6mm (the opposite to what you are doing with a spacer) to get the chain to line up without hitting the frame. Some 180 tyres (Shinkos for example) actually measure 190mm so check that too.

Lorcan wrote:

What wheel are you using and are you absolutely sure it's centred?

I'm using a 6" Hayabusa wheel with a 180 Racetec Metzeler tyre and a 10mm offset front sprocket with a 530 o-ring chain and it clears the tyre by about 3-4mm. I had to machine the sprocket carrier down by 6mm (the opposite to what you are doing with a spacer) to get the chain to line up without hitting the frame. Some 180 tyres (Shinkos for example) actually measure 190mm so check that too.

The wheel is actually a modified KZ wheel. Was a standard 3x16 and is now a 6x17. The wheel is centered and straight. It has eccentric adjusters so it's pretty much self aligning. I'll measure the actual width on the tire. It probably is a little over since it's on a 6" wheel.

79MKII wrote:
The wheel is actually a modified KZ wheel. Was a standard 3x16 and is now a 6x17.[/quote]

Well that explains the positive offset on the rear sprocket. I assume you did that to keep the look of the original wheel, although they are heavy. Let us know how wide your tyre actually is, I'm sure there's a solution within reach

Lorcan wrote:

Well that explains the positive offset on the rear sprocket. I assume you did that to keep the look of the original wheel, although they are heavy. Let us know how wide your tyre actually is, I'm sure there's a solution within reach

I appreciate your optomism, Lorcan! I was pretty bummed out then I tried to install the drive chain. I had centered the wheel and aligned the sprockets before everything was chrome plated and powdercoated and thought I was OK. Yes, I had a stock wheel modified so it would match the front. I ended up having that widened too, so I probably should have gone aftermarket after all.

By the way, you mentioned that you have 3-4mm tire/chain clearance. Is that about the minimum in your opinion? I'm not sure what to shoot for either. 4mm is only about .157", but I'm hoping that's plenty.

Post edited by: 79MKII, at: 2007/12/02 20:02

I had the same problem and used a 170mm tire to get clearance. now that its done i think i will buy a 180mm next time and trim the tire.
try an angle grinder, and get someone to turn the tire on the bike , while u trim.

mark1122 wrote:

I had the same problem and used a 170mm tire to get clearance. now that its done i think i will buy a 180mm next time and trim the tire.
try an angle grinder, and get someone to turn the tire on the bike , while u trim.

I think trimming would be easy and work well, but I"M SCARED!! :blink: :blink:

btw, I haven't been able to find a 170 tire that is mountable on a 6" wide rim. Should have gone with 5.5"!

Post edited by: 79MKII, at: 2007/12/02 21:08

So did you measure your tyre?

3-4mm is plenty. I've trimmed a tyre before, it was a 170 Metz stretched onto a 6" CMA rim back in the late eighties. We had an offset sprocket ( I think ) but it still had the 630 chain on so it rubbed, we just took the shoulder off the tyre with a razor blade. I think the angle grinder would have worked better but we didn't think of that at the time. It handled pretty awful but was only for dragging so it didn't matter.

Needs must when the devil rides! :evil: :laugh:

I realized that I don't have a good way to measure it. I eyeballed it with a tape measure and it looks to be exactly 7" which is around 178mm. I don't think it's bigger than 180. I 530 chain I have is very heavy duty and an o-ring type, so it's very wide. I think a different chain would definitely help too. I was surprised to learn how much chains of the same size vary in width. I've spent many, many hours researching and checking specs since this all happened...:blink:

i used a non oring chain to gain clearance.

Is there an intelligent way to estimate how much rubber can be removed from a given tire?

Regarding the chain width - my old 630 non o-ring type is more narrow than my new 530 chain. They have 520 chains now rated for 1000cc and about 150 hp. I really wanted to buy a 520 racing chain (non o-ring) but can't find one anywhere over 120 links and I need 126. Those are a full 8mm more narrow than my new 530.