[cmc]

i am running 30-14 on an '08 MOB. with a regular chain the axle is either too far forward (too tight to work with without grinding dropouts which i dont want to do) or add a link and the wheel is too far back, with part of the bolt hanging off the back of the dropout....

so i was running a half-link which puts the wheel right in the middle of the dropout. now, two broken half links later...

i am wondering if i switch to 28-13, will it that create a spindle to axle length that doesn't require a half link.

i have a KHE half-link chain on my other bike (all half-links) but it seems heavy... i'll go that way if necessary....

 

[jerseydirt]

I have a 25-14, its pretty terrible, the only way I could make it work is if I had a set of cranks with a longer spindle? Anyone up for a trade, I have primo powerbites in black.

Your best bet wold be to get a 28-13, and f you want a lighter chain, get a hollow pin half link chain, can go wrong.

 

[cmc]

I have a 25-14, its pretty terrible, the only way I could make it work is if I had a set of cranks with a longer spindle? Anyone up for a trade, I have primo powerbites in black.

Your best bet wold be to get a 28-13, and f you want a lighter chain, get a hollow pin half link chain, can go wrong.

No, cranks are not your issue. It's gear ratio plain and simple. The easy rule of thumb for choosing a front sprocket for 26" wheels is double the rear cog plus 2. So 13X2= 26+2 = 28. 28-13 is a good all-around bmx style single-speed gear. (xc climbers usually like something spinnier, i.e. 2:1 gear ratio).

The formula is front teeth divided by rear teeth multiplied by wheel diameter.
28 / 13 X 26 = 56. Your goal should be in the 54-58 range.

25/14 X 26 is only 46.4. You'd be better off dropping down to 11 or 12 in the back, instead of 14. Then you'll be fine.

 

[Bikael Molton]

I have 28-13 on my 09 mob, with a Kool Chain SL plus 1 half link. Axle is just about in the middle of the dropout. If I grind the dropouts an 1/8" or so, it will fit w/o a half-link. I will probably grind the dropouts soon, as I run a 1.9" tire and have plenty of clearance.

I do have a 12T kicking around that isn't compatible with the Kool. Long term I'm going to try a new SRAM PC-7X chain with the 12T.

-r

PS - aesthetically I don't like the look of anything smaller than a 28T on a 26" bike.

 

[t1maglio]

CMC, I had the 27-12 on my mob. (I toyed with a 26 as well, but it was kinda light). I didn't have a half link on there but I had it buried in the dropout (to the point of having to take the crank/sprocket off to remove the wheel). It worked pretty good, IMO as far as keeping a good tight back end and good gearing. To off set the wheel issue you could actually grind out the drop just a touch to get the little slack you need, but that can be your call.

 

[jasride]

yeah, i was running a 28-13 all summer long with a half link chain. Fits easily in the drop out, no problems. I ride an Eastern dj4, not sure if the drop outs are the same as what you have. Sure the weight of the half link chain could be a tad more but really to me it's no big deal. Plus I like the look of 1/8" thick half links.

 

[sittingduck]

I run 27/12. (2.25:1)
It's almost too light....
Sounds like it will fit the mob better too. See if you can trade your 28 for a 27. You'll need some thin spacers for a 12 if you use a cassette hub too.

 

[t1maglio]

Gusset double six will take care of that backend real nice!