changing to singlespeed from a hybrid

2wheelzgood

Just after a bit of help really in deciding what bits to get and how to go about it.
My rear mech cable snapped on my Dawes 301 the other day and I was stuck using the middle front (38) and smallest rear (11 I think). It was tough and Leeds ain't that flat but I loved it! Although I was worried about the increased forces going through the older nasty chain and adjustable (yuk) handlebar.

I'm gonna just make it a SS.. although bought a new gear cable so I can get to work in the meantime.

I've been into my LBS and know what basics I need but if anyone has tips on gearing or what makes to get, that would help source.

-wide bar (one of the guys there showed me his 26" rigid MTB with a trials style wide bar with rise, said it really helps with leverage), rise? think not on a dawes hybrid

-stem on a road bike, probably a flat-ish one? any rise?

-good cranks and chain set, deore or better, 165mm suggested although on the dawes now it's 170 and I'm happy

-gear ratio, on 26" I've read 32-16 although It needs to be more teeth up front with 700c wheels, right? 42 too much? my middle is 38 so 38 with a BMX rear 16 will be easy-ish?

- rear cog , spacers (from a hacked up 8speed cassette?) and chain. I;ve been told a thicker BMX chain is best..?
Also, with the wider cog on the back, is it still ok to use a 3/32" chainring up front.. can;t find any 36T 1/8" ???

-chain tensioner.. I've see a few, spring loaded look best, but some pull up wrapping the chain round the cog better, some push it down (not ideal IMHO).
Also are ones with a jockey wheel and cog better then the ones where the chain runs through the middle of a plastic V thing?

I'm reasonably fit cyclist, use a few gears but can avoid the steepest hill on the way home until I build up I guess. I want it to work but be cheap. and I do realise I won't be able to cut through the woods and go up the steep hills like I do now sometimes in my lowest gear, oh well. I may even take the crossroads tyres off and put the skinny ones on once it's all set up for SS

thanks for any help.

johnnyhotdog

hi - i don't know if this helps, but i use 42/16 on my fixed and find that perfect for around leeds and longer rides to skipton etc. (700c wheels.)
.

2wheelzgood

Nice one thanks Johnny. I was thinking 38 16 to begin with.. I'm in Roundhay and commute to Uni so hills up and down each way. I can avoid the steepest ones by altering route slightly I guess.

I'll have to look tomorrow to see If I can use my acera cranks.. I have a ffeling it's a cheap thing and the middle and small rings are locked on..(worn too)

I've thought about the bars... not sure I want wide bars with the rush hour filtering I'll be doing.. not sure how much easier it is with extra leverage.

rooford

I've been riding single speed / fixed for 6 months and can give you a heads up on a couple of things.

I'd stick with a 1/32" chain width, they're more common and you'll get a better quality of chain for your money than a 1/8". You will also have more options with sprockets too. A 1/32" chain will also cope better with your chain line being slightly out, so you don't have to be so precise with lining up your back and front sprockets. I wouldn't advise mixing sprocket widths. Don't worry about strength 1/32" are used by pros without issue.

You will find you "wear" out your sprockets a lot quicker as you only use one gear. Chains don't wear they stretch. The more teeth you have the less they'll wear as they don't go around as often (they're bigger) and you'll have more teeth in contact with the chain so less stress in each tooth/chain pairing.

Most people stick with a gain ratio of 70". Look on line for a gear gain calculator. I run 48t / 20t to give approx. 70" gain with 700c and live in a reasonably hilly area. I gained strength pretty quickly and now spin out at top speed so maybe a higher ratio would be better.

Most people advise running a 20 tooth minimum on the back sprocket to reduce wear issues although there's a weight penalty with larger sprockets. I'd also suggest you try and get sprockets with out the ramping (this helps the chain ramp up and down when you change gear) as you don't want the chain to skip off the sprocket when you're powering up hills.

Regarding cranks, depending on your height unless your legs are short I'd stick with longer cranks, particularly if you need to get up hills. It will give you more leverage. I got knee pain when I swapped to 165mm cranks I've since swapped back to 175mm.

I guess the 165mm suggestion was given to increase ground clearance which is reasonably important on a fixed speed (you don't want to ground the pedals) with a single speed you can free wheel so it won't be an issue.

I ride with drop bars after always riding with flat bars and have never looked back. You have more options with hand positions and can get into a low position, it makes a surprising difference. I don't have much problem with leverage, but going this route would mean replacing your brake levers.

Good luck with your project

2wheelzgood

Thanks dude... some really usefull tips there. I'm lookin gup prices of bits today then heading to my LBS!

38 16t on my wheels is a 64" gain so I think that will work..

Yup had seen next to no choice on bmx cogs and chains so will stick to 3/32

william79

I find the On One 'Midge' handle bars are a good compromise between road and mountain bike versions. They give plenty of hand positions & you can drop down in a head wind. The are quite wide but comfortable. You would need new brake levers with these too.

I started riding fixed (700cc) with 48x18 and found it too spiny, settling on 48x16 with 175mm cranks; not many big hills on my route.

I would consider the Surly Chain tensioner as it allows you to adjust the line of the jockey wheel to match the chain line. It's probably worth spending a bit more on this part as it is always touching the chain; I've heard some with a plastic wheel are a bit noisy.

I'll be interested to see how you get on, as I'll be converting my mountain bike in the near future.

2wheelzgood

Those bars do look useful. Luckily my commute isn't that long so I don't normally find myself wanting lots of hand positions. I have bar ends which may or may not stay on.

I'll be getting a non-adjustable stem about the same size as how I have my self-loosening adjustable one at the minute... 125mm I measures so will buy 120 as 125 is unobtainable.
6 degree rise or something and stick with my fat(ish) bar for the time being.
FSA XC170 any good?

I've bought a 3/32" half link chain today and am going to get a DMR chain tensioner without the jockey wheel. There's a bloke in my LBS in Leeds who is entering th SS championships up in Dumfries and has a neat SS rigid moutain bike so he knows what he's on about.
he has a DMR tensioner up front right next to the chainring/bash guard.. looks dead neat.. and you a) don't get the tensioner pushing teh chain up onto the underneath of the chainstay at the rear and pushing up at th front means you get even more chain ring wrapping!
Plus it looks awesome!

Only works with up to 33t rings though, so mine's on the back.
Hopefully with the half link chain and the design of the Dawes chainstays, it'll be just right.

I'm looking on ebay for 175mm crank sets and will get a 38T ring.

I've ordered a Shimano DXr 16t cog and CNC machined spacers from the ebay seller Londonfixiebike. top seller


and once I get it all, it's back to the LBS to have it all fitted cos I ain't spending another 20-30 on tools I'll use twice. crank remover, casstee tool, chain whip...etc


meanwhile I've put a gear cable into the bike so I can ride to work but the chain and mech are so shot it's not that handy.. I'll keep it in the ratio I plan to use to practice!

thanks for the support.

2wheelzgood

I'll update you later today william. It's just about done and mega fun.
go for it! 8)

SamWise72

No need to go to shorter cranks - they help if you're going fixed, because they avoid pedal strike when pedalling round corners, but for SS, there's no real advantage. If you ever want to do the job on the cheap, pvc water pipe can be had for very little money that's the right size for spacers. Pick up a length at your local B&Q, and for a couple of quid, you can make spacers for 20 bikes!