Singlespeed advice

[claret73]

Took the Trek, now a modified SS for a quick blast round the block the weekend. But when I go up a steep short hill, there is a slipping at the back?

I have Vertical dropouts with a QR. The hub is a 7spd, spaced out with Velo Solo spacers to a Surly 16th. I'm using the Surly Singulator for chain tension & am happy this is tensioned enough. The spacer next to the lockring overhang the freehub body by about a couple of mm, so have had this machined down to fit near enough smack on the edge of the freehub body. I did at one point overtighten to see if it may be too loose but then the freehub didn't rotate as freely...

I don't know if this has cured it yet, but any ideas or what I'm doing wrong if it doesn't fix it? It's fine until you put tension on it; ie: spinning on flat=fine. Grunt up a hill=slippage...

 

[feetabix]

could it be wear to chain or teeth?.......

 

[claret73]

Nope. All drive gear is Brand new!! New chainring, new chain, new sprocket & rear hub was stripped right down & repacked...& that's OK, not loose on the cones or freehub...

 

[velomaniac]

Could it be not enough chain wrap around the rear sprocket.
Shouldn't be if your using the singulator pushing up but might be if its pushing down. With smaller sprockets you need more chain wrap as there are less teeth to engage with the chain. Under load if there are not enough teeth engaging the underside of the rear sprocket the chain can slip off the top teeth.

 

[mikee]

chain line okay?

 

[claret73]

Velomaniac...you may be onto something there...I am running it pushing down, although wanted up but this is how it came to me, so left it, but will look to change it I think now...if I have the Spring? (chain wrap finishes in line with Derailleur thread)...

Mikee, Chainline OK, did the Sheldon Calc...

 

[Harryburgundy]

Velomaniac...you may be onto something there...I am running it pushing down, although wanted up but this is how it came to me, so left it, but will look to change it I think now...if I have the Spring? (chain wrap finishes in line with Derailleur thread)...

Mikee, Chainline OK, did the Sheldon Calc...

I'm with Velo as well...not enough chain wrap...what ratio/rings are you running...I tend to run big and big to get good wrap

 

[claret73]

Carl,
I'm running 32x16...& am with you both now on the wrap. Have just changed over the spring & will sort it tomorrow to see if it's helped...
Thanks Guys!!

 

[jimihendrix]

This same thing happened to me when i first built my SS, was using a DMR push down tensioner, in frustration i took the tensioner off and tried fitting the chain without and it worked, sometimes you can get lucky with chainstay length and can run without a tensioner, with 32-16 a new chain was slightly tight but would slacken to perfect after a couple of rides, fitted a new chain every two months or so.

Cleaner looking and quieter running with no tensioner, worth a try

 

[DM]

What Harry said:
I use old 110mm chainrings in larger sizes. Same gear ratio; more chain-wrap.

At least you don't have a constantly creaking eccentric BB like mine :roll:
It takes about 4 different tools, 3 hands, 2 beers and 1 tube of copper-grease to adjust it every couple of months. :evil: