Guys,

While my bike is apart right now, I was thinking about going ahead and doing a chain conversion. While the stock 160mm tire and 4.5" wide rim is staying on for now, the next upgrade will include a 180mm tire on a 5.5" rear rim.

Looking at the chain conversion thread by Lama, I found a pic by monster715 with a stock tire:




This is with the .500" offset front sprocket. I am wondering if I need to go with a .750" offset front sprocket to gain additional clearance.

Is anyone running a 5.5" wide rim with a 180mm tire, and if yes, do you have enough clearance with the .500" offset sprocket?

Thanks,

Dave

 

I am running a 5.5"/180 with a 530 chain but it's on a 5 speed bike with a custom wheel so my spacer is different that normal. I only have a tiny bit of clearance. Maybe .060" or .100"? Can't recall exactly right now. No rubbing at all. Works great for me. Alignment is critical, tho.

 

Did you try to center the wheel on the frame, or did you move over the tire/rim to get that clearance.

I forgot to add in my original post that I am going to try to center the rim and tire on the frame, so judging by some of Nemosengineer posts, stock the tire and rim are moved over about three eights to the air cleaner side.

Thanks,

Dave

 

Everything is centered. It's a customized hub, custom spacers (all 3), and laced up by me. It's set up so there is no lateral offset to the lacing.

It's probably negligible in real life but I was concerned that offset lacing would allow a certain amount of yaw under load.

 

So I went ahead and got the pieces for the conversion:

PBI front sprocket - 3/4" offset - pn 302-25
PBI mainshaft nut - pn 291
PBI 2072 aluminum rear sprocket with 55 teeth and 2.214" center hole - dished 0.245" -pn 2072-55
EK 530 DRZ2 120 link chain - pn 530DRZ2 X 120
Bungking 06 and up chain slider - pn DCS06

The final gear ratio will be 2.976 and 6.667% lower than stock. When I put on the 180/55-17 tires later on, it will have equivalent to being 11.07% lower than stock, just a couple percent off than doing a 30/70 pulley set-up with a stock height tire.

I like the look of a dished sprocket in comparison to a flat one. I will post what the spacer dimension turns out to be when finished. I am not centering the tire with the stock rim set-up. That's for later with the wider rim.

Peace.

Dave

 

First, some pics:

 

 

The spacer (with the spec'ed out parts from before) was 0.875" and 0.060 had to be machined off, leaving a final dimension of 0.815" for the spacer.

The clearance between the chain and tire is 1". I measured the width of the stock tire (for a FXDLS) and it was 160mm (or rounded to 6.3125")

So with the above information:

If it takes 0.300" of shifting the tire to the clutch side (what Mike, Nemosengineer, found on his 2009 Dyna) to center the tire on the frame.

The 180mm tire is truly 180mm (or rounded to 7.0625).

7.0625" - 6.3125" = 0.750" / 2 = 0.375" (180mm tire and subtract 160mm tire and divide the difference by 2)

1.000" - 0.300" = 0.700" - 0.375" = .325" theoretical clearance (1" original clearance subtract the 0.300" offset and subtract the added width of the 180mm tire)

So....if I used the 0.500" offset transmission sprocket, I would have had 0.075" clearance (a little above 1/16") between the tire and chain (with centered 180mm tire). I personally think than would have been too close. With the 0.750" offset transmission sprocket, I will have 0.325" clearance. Room for a 190mm tire, lol.

I hope this helps anyone in the future. If you don't center your tire in the frame, a 0.500" offset sprocket is more than enough for a 180mm tire.

Remember all this is for a 2006-2017 Dynas.

Peace.

Dave

 

Better buy a couple spare rear sprockets those pretty alloy alum. ones chew up fairly quick. Tried them on my old shovel and it ate it one summer. Be on the lookout for a better quality o-ring chain too.

 

The sprocket for sure I will be keeping an eye on. The chain is the top of the line non-o-ring chain. Hunting for 150+ horsepower on the dyno, and the little things add up.

Dave

PS. Hello neighbor, Fremont here.