Cheap SingleSpeed Conversion...Help wanted

bigdawg

Ok my 12 year old cannondale has been dusted off for single speed duties, but dont know where to start re conversion.

Dont want to spend much money so a swap of the brake levers and mechs off. re the rear wheel dont really want to start rebuilding on new hubs so what are my option, hub spacers and sprocket, or can I take the freewheel off and replace it with something else? (dont want it fixed at the mo). Also crank do I just use the 39 inner ring??

any help appreciated here....

peejay78

does it have vertical dropouts?

you may have to get an offset hub.

if running SS you could use a chain tensioner.

it's complicated.

demmerson

If it's an 8 speed Shimano freehub you could try the On-One Singlespeed Converter. http://www.on-one.co.uk/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=74&MMN_position=80:80

bigdawg

that on one thing is exactly what Im looking for...

whats a good street ratio with a 16 rear, will a front 39 be rideable??

nicklouse

bigdawg

just a word of warning. if the freebody (cassette carrier) is made from aluminium that type of cog will cut into it.

both Surly and Gusset make SS kits with cogs witha 7mm wide base.

if yours is steel then no worries.

bigdawg

Ill look out for that, but from memory it was plastic... :?

Ill do a google for them, thanks for the advice, Im pretty heavy on the pedals

Bronzie

bigdawg wrote:

whats a good street ratio with a 16 rear, will a front 39 be rideable??

That's about 66" which is a fairly standard fixed-wheel gear - at a cadence of 90rpm, you will average about 17mph. You may find it a bit small if all you are riding is flat terrain though.

bigdawg

Bronzie wrote:

bigdawg wrote:

whats a good street ratio with a 16 rear, will a front 39 be rideable??

That's about 66" which is a fairly standard fixed-wheel gear - at a cadence of 90rpm, you will average about 17mph. You may find it a bit small if all you are riding is flat terrain though.

excuse the nube questions but if I wanted to increae that is it better to increase the rear or front cog, and is there a chart anywhere detailing ratios & speeds??

Bronzie

bigdawg wrote:

excuse the nube questions but if I wanted to increae that is it better to increase the rear or front cog, and is there a chart anywhere detailing ratios & speeds??

I'd say increase the chainring size - simply because 39T is about as small as you'll get on a standard Shimano crank.

To work out speed (mph) for any given gear:
(number of teeth on front) divided by (number of teeth on rear) x (wheel circumference = 2.1m for standard 700c tyres) x (cadence rpm) x 60 (minutes) div by 1609 (metres in a mile)

There is a gear inches table in the back of the Cycling Time Trials handbook (if you are of that persuasion), or make your own with the above formula and an Excel spreadsheet!

.....................or you could try this:
http://www.sunderlandclarion.org.uk/cadence.htm
......................or this:
http://www.roygardiner.com/gears.htm

nicklouse

Bronzie
but would it not be easier to go smaller on the rear? chain shortening rather than lengthening.

you could go down to a 12T at the back if you wanted but then there are other issues to think of.

Bronzie

Dooh! I was going the wrong way anyway! To get a bigger gear, you need a bigger chainring, not smaller. :oops:

The only problem with changing the rear sprocket is that sometimes the jump can seem a bit big - easier to "fine tune" the gear by changing the front - example:
39x16 = 65.8"
39x15 = 70.2"
42x16 = 70.8" but you could opt for a 40T or 41T on the front instead

nicklouse wrote:

you could go down to a 12T at the back if you wanted but then there are other issues to think of.

Like your knees!

bigdawg

ive been riding it in 39/14 (without changing gear) for the last three weeks just to see what its like and Im coping with all the hills I normally ride real easy, so I may take a go at 39/13 to see how I go for a week or so...

steverile

39/13 is getting on for a track gear -- are you fast? If it was me I'd start off easier. Big gear=harder on knees in my limited experience. Enjoy the spin!

bigdawg

I can push big gears and as some of the younger guys round here will tell you Im also quite good at climbing, Im gonna try 39/13 for a week to see how that goes on the hills, although I may be a bit ambitious especially with winter approaching