Singlespeed conversion/dropout question

[blueovercream]

As a bit of a winter project I'd like to build up a single speed bike.

I know that you need a frame with horizontal dropouts (or else use a chain tensioner which sort of spoils the look for me).

Many old road frames have almost horizontal droupouts, in that they're slightly angled but still have a reasonably long "track" in which the axle could slide. Some are longer than others. Is this sufficient to generate chain tension, or do they need to be truly horizontal?

Thanks

[DB531]

How you achieve your project will really depend on the length of the chain stays and gap between the wheel/tyre and seat tube.

If you go for a vertical drop out, a chain tensioner will be needed.

Forward drop out of reasonable length will work. never found the slight angle to be a problem. Check on wheel/tyre to seat tube gap.

Rear drop out just makes removing the wheel a bit more of a chore.

If you are going to fit mudguards remember to budget for extra clearance, if fitting mudguards to frames with rear drop outs remember to leave the rear stays long, so as to allow for wheel removal.

Worth checking the compatibility of the frame to the hub of choice.

[zax]

My fixed gear bike is built on an old road frame, forward facing dropouts with a shallow angle and reasonable length. No tensioner. Never had an issue with chain tension, perhaps a very slight loosening but not enough to need adjusting until it's time to fix a puncture/change a tyre/clean the bike anyway.

[blueovercream]

Useful thank you both.

I hadn't thought about mudguard clearance which is a good point!

[Tom _M]

As mentioned, think about hubs too. An ‘off the shelf’ track/single speed wheel will likely be spaced for a 120mm rear dropout. Older steel frames likely to be 126mm (IIRC), and newer stuff (90’s onwards) 130mm.

[Ryyy]

I had a fixie that was an old racer conversion with vertical dropouts and I feel that had good enough tension for just riding around. I have recently Bought a mango fixie though needing tlc a couple of weeks ago to scratch an itch and you can tell how much better it is/ the tension is for obvious reasons

If you're not doing sick skids m8 and not brakeless I'm sure it'll be fine

[anonymous-user]

Don’t fixie frames also have grub screws in the horizontal rear drop outs to fine tune the chain tension? Not sure how you’d replicate that in an adapted road frame without some other means of tensioning the chain.

[klootzak]

The angled drop-outs on my single speed converted 70s Falcon provide plenty of chain adjustment scope, though wheel alignment can be a bit of a pain. Solution to that is to get some DMR or Surly chain tugs, which seem to fit on angled drop-outs just fine and allow quite precise adjustment on each side.

If you're putting 700c wheels on a frame previously equipped with 27" wheels you'll have epic amounts of space for mudguards, but will probably need new (deep-drop) brakes.

k

[Ryyy]

BlackWidow13 said:

Don’t fixie frames also have grub screws in the horizontal rear drop outs to fine tune the chain tension? Not sure how you’d replicate that in an adapted road frame without some other means of tensioning the chain.

Do you mean chain tugs? The little doofers that you tighten at the back of the dropout?

Also just seen this
https://www.bricklanebikes.co.uk/blb-single-speed-... should pick up all the slack

Edited by Ryyy on Thursday 15th September 08:15

[james0]

Ive run a few bikes single speed and the neatest, least faff, works with disk brakes and easiest to get the back wheel out method is to use a tensioner at the chainset end.

It doesn't need to be sprung and looks very neat.

I've made one in the past. Or you can use a chain device for a downhill MTB. MTBs tend to have tabs to mount the chain device but you can get adaptors which sandwich between the frame and BB.


Like this
http://www.on-one.co.uk/files/oo/rides/900x650_con...

Edited by james0 on Friday 16th September 19:28

[Fastpedeller]

Road bike 'horizontal' dropouts will work ok as some have said. I'd suggest a 1/8 chainring, chain and sprocket will feel and also run better, for either a single freewheel or fixed wheel, and IMHO is essential if using fixed wheel. A chain tensioner cannot be used with fixed wheel (you probably already know that though)

[shalmaneser]

Another option is to use a bb30 road frame and get an eccentric bottom bracket. I've been running one for 10 years or so and it works very well indeed.

Obviously potentially a bit more pricey but a better solution than a tensioner imo.