Anyone Run a 18/48 sprocket combo on 955?

[jwray76]

Did a bit of searching and didn't find much on this gearing configuration. Lot of guys went with a 17/46 and like the low end but not the highway manners. I would like to gain some low end (1st gear is tall!) but not give up too much on the top end for highway cruising. Looks like a 18/48 combo could do this. Any experience?

FWIW I am looking at this combo because it falls in between stock and the 17/46 setup. Also I don't like going down in the front because it puts more stress on the chain and hits the rub blocks more.

[Mustang]

the transmission gear ratios on a 955I and the old t3 motors is the same
steamers came with 18/48 final drive . the 1st gear on a steamer is still a little tall for true off road work
17/48 is better but adds 500 rpm to every gear your in

stock Girly is 18/46 which is a ratio of 2.55:1 aprox.
17/46 will give a final drive ratio of 2.7:1 approx.

and 18/48 will give a final drive ratio of 2.66:1 approx

[jwray76]

Thanks Mustang...so it sounds like the 18/48 is a pretty good compromise to get a little more on the low end without loosing much on the top. Guess Triumph thought that with the extra grunt of the 955 they didn't need the gearing of the Steamer. But I think the first gear is even tall for street riding.

[jwray76]

By the way is there a lower rub block on the 955? I don't see one on the bike bandit diagram[/img]

[Mustang]

yep item #2 on the main frame and fittings microfiche

[Bixxer Bob]

I'm guessing this is an early Girly then?

[jwray76]

I am referring to a 2002 955i model.

By the way I just want to double check to make sure I haven't missed anything and that it really is the chain that is bad...

When I spin the rear wheel the chain gets tight at one spot each revolution. Pretty significant change from loose to tight.

It doesn't appear that any of the rollers are locked up and that ther are kinked sections of chain.

I measured the 20 links for 12.5" in quite a few places and didn't really notice much difference but it was kind of awkward to measure. Seems that it must be stretched in one area though.

I rigged up a ghetto dial indicator that measured from the swing arm to the outside edge of the rear sprocket and there didn't really seem to be any run out at all so the back wheel looks straight.

So from this analysis would you agree that it sounds like a bad chain?

[iansoady]

If the tight spot is at the same place in each wheel revolution that points to a problem with the wheel / sprocket rather than the chain itself as with the chain it would move around (as the chain length isn't an exact multiple of the sprocket teeth).

[jwray76]

If the tight spot is at the same place in each wheel revolution that points to a problem with the wheel / sprocket rather than the chain itself as with the chain it would move around (as the chain length isn't an exact multiple of the sprocket teeth).

hmm good point...I didn't pay that much attention to the frequency of rotation but it seems that it was the same spot in the chain each time and not the wheel...maybe I need to make some marks and check that out.

The bike has only 15k miles so it could still be the stocker but doesn't appear so. The rear sprocket is made by Sunstar and the chain is DID. Rear sprocket is in good condition but the front is hooked a bit.

[jwray76]

So I took some more time tonight to look at it and the chain is definitely the culprit. each full revolution of the chain provides exactly one tight spot in the same place each time.

While I was messing around I took a look at getting the rub blocks out. The top one on the swing arm wasn't a problem to get out and could definitely use replacing. The bottom one that goes over the spacer between the frame and engine is a pain to get at. I got the bolt out and had everything supported and that spacer was wedged in there good and didn't even move. Therefore I will make the decision that the bottom block is still in good enough shape  

[jwray76]

Looking like both of the rub blocks might have to do for now. Ordered teh swing arm one but It is on backorder from the dealer.

Getting back to the original topic though I did order the 18/48 sprocket combination! Hopefully I will be happy with this set up. Thinking that I may run the chain at 115 links long to make up for the larger sprocket.

[jwray76]

got the new chain and sprockets installed on Saturday and went for a few hundred mile yesterday. Unfortunately I didn't get to ride the bike much with the 18/46 sprockets...but I really like the gearing with the 18/48.

1st gear is still plenty tall and I don't feel like I am looking for another gear when cruising. I would recommend this as a great alternative to stock that just makes the bike a bit more snappy.

By the way I still cut the chain down to the stock length of 114 links/pins and it works well.

FWIW I used JT steel sprockets and a bikemaster O-Ring chain. I was a little nervous about the bikemaster chain, but it appears to be quality and actually if I remember correctly it was stamped as an EK chain. I will take a look at what model EK chain it is in case anyone is interested.

[hooligan971]

JW,
 Just wondering how you are liking the new ratio after riding with it for a while. Where did you order from ? I'm over in Mathews County but just bought a place on the other side of you near the mountains in Buckingham Co. although I haven't ridden out there much yet.

[jwray76]

JW,
 Just wondering how you are liking the new ratio after riding with it for a while. Where did you order from ? I'm over in Mathews County but just bought a place on the other side of you near the mountains in Buckingham Co. although I haven't ridden out there much yet.

Really liking the setup..if anything the gearing is still a little tall, however for interstate cruising I don't think I would want the gearing an lower. I picked up the chain and sprocket set from ebay seller "Jawzys". Shipped quick and the items were all as described. The chain does come in standard 120 link length so you have to cut it down.