gear ratio

[malverncyclist]

On my old TI Raleigh 12 speed bike I find that I only use my lower 6 gears and do somewhat struggle up hills. Just did the 'tooth' counting and have the following:

front 52/42, rear 14/16/18/21/24/28. The rear cassette was already 'downgeared' from the original.

now, not a techi, me, but I need to get my head 'round how to improve the ratio to use the 12 gears I have AND obviously get up hills more easily.

Any advice?

tahnks

Martin

[Brucey]

smaller chainrings (= new chainset probably). 46 and 32t rings would do it.

there are other ways I'm sure but that'd do it.

cheers

[meic]

The lowest chainring change that I think you will be able to make on that chainset is probably to change the 42 for a 38 tooth ring.

That would help but just a little.

It is probably time to bite the bullet and buy a triple chainset which will want a new bottom bracket and front deraileur to accompany it too at a guess.
Then you can have the luxury and bliss of effortlessly crawling up hills with a chainring of 28, 26, 24 or even 22 teeth.

There is a dodge for keeping your old front deraileur, have the two larger rings on the triple quite close in size and then a double front deraileur will work better than a triple one.
eg 48, 42, 28 chainrings

You could go halfway and buy a "compact" double chainset which will most likely just need a new bottom bracket. That will get you down to 34 teeth on a front chainring.

I am assuming that you have old fashioned friction gear levers with no clicks for the front changer.

[tatanab]

buy a "compact" double chainset which will most likely just need a new bottom bracket. That will get you down to 34 teeth on a front chainring.

Given the price of decent chainrings, this is probably your cheapest answer. You probably will not need to change the bottom bracket either.

[thirdcrank]

This is the "sports bike" arrangement I've moaned about before.

Presumably the current cranks are some Raleigh own-brand lookalike version of what was once called "old Campag."

The chainrings you can fit depend on the BCD

http://www.sheldonbrown.com/gloss_bo-z.html#bcd

If it's an exact copy of old Campag (144mm) it's new cranks or put up with the current chainrings. If it's something different, then smaller rings may be possible.

I'd suggest looking at this before replacing the whole BB + cranks.

[Mick F]

I had a few bikes with "old campag" dimensions, and when I became serious about cycling I did some research.

After taking advice, I splashed out on a Stronglight 99 double and matching BB. The 99 could be fitted with a wide variety of rings and converted to triple if required. I ended up with a collection of 36t, 38t, 40t, 42t, 52t and 53t rings! I changed ratios as the routes and situations dictated. I still have all the rings and cranks.

So my advice is the same as TC's - do some checking to see what you have already and if you can fit different rings, but if not, it's new chainset. Make sure you get one that can take different sized rings in the future.

[Brucey]

I don't know if they are still available or not, but at one time you could buy a 'special' inner chainring for a double that would have a third, tiny one hung off the inside of it. This allowed a double to be converted to a triple, (although I think you maybe had to cut the 'shoulders' under the original small ring off the crankset). Before these were available I made my own from a pair of specially machined stronglight 99 chainrings, thus getting a 30,42,52 chainset.

The downsides to this approach are that a new BBKT is likely to be required and maybe new mechs with a big enough capacity. But it is another route.

cheers

[thirdcrank]

... at one time you could buy a 'special' inner chainring for a double that would have a third, tiny one hung off the inside of it. This allowed a double to be converted to a triple, ...

I think they were from TA. I've not seen anything of that type advertised for a while but TA stuff has never been cheap.I did a google to see if I could find a pic of the TA convertor ring. That took me to this on Sheldon Brown:

T.A. triple conversion chainrings include the necessary bolts and spacers to attach a 74 mm granny chainring.

Unfortunately, following the links to the Harris Cyclery stock pages draws a blank.

In any event, conversion to a triple does involve a bit more than just fitting an extra ring.

[meic]

Still available from Stronglight though.

http://www.spacycles.co.uk/products.php ... 0s149p1141

http://www.spacycles.co.uk/products.php ... 0s149p1936

[Mick F]

With my 99 Double all I would've needed were longer bolts and a set of spacers to turn it into a triple. And an inner ring of course!

Just like Meic's link from Spa.

[thirdcrank]

Still available from Stronglight though....

Looks as though they are only for a modern BCD.