172.5 or 175

retrobike007

Have bought a halfords road bike and I want to upgrade the front chainrings, as it has a 38/48, and I want 53, the cheapest way seems to be a new chainset. Campag mirage or similar, they all seem to have different arm lengths, whst the difference in the arm lengths?

redddraggon

retrobike007 wrote:

Have bought a halfords road bike and I want to upgrade the front chainrings, as it has a 38/48, and I want 53, the cheapest way seems to be a new chainset. Campag mirage or similar, they all seem to have different arm lengths, whst the difference in the arm lengths?

Cheapest way mate is to just buy a new chainring. Every LBS or online bike shop sells chainrings on their own.

No need to buy a new chainset

skyd0g

Depends on the BCD - the current compact will prob be 110mm BCD, a 53 chainring will prob need a 130 BCD.

redddraggon

skyd0g wrote:

Depends on the BCD - the current compact will prob be 110mm BCD, a 53 chainring will prob need a 130 BCD.

You can get 53t rings in 110mm, 130mm , 135mm and a load of other obscure BCDs so it's not an issue.

PeeDee

You'll need a new chain too since the old one will be too short for your new 53 chainring. Its also worth buying the spanner/tool thingy to fit the recessed bolts holding the chain ring to the arms on the crankset.. You can frig it by tapping them round with a screwdriver, but not very satisfactory really.

PeeDee

BTW cranks usually range from about 160mm to 175mm. Basically, the longer your legs the longer your crank. Having said that, its really down to personal prefernece how long a crank you prefer.

a_n_t

175 on my road bike
172.5 on my TT bike.


Cant tell the difference at all tbh!

retrobike007

PeeDee wrote:

BTW cranks usually range from about 160mm to 175mm. Basically, the longer your legs the longer your crank. Having said that, its really down to personal prefernece how long a crank you prefer.

Thats more like the info I was looking for.

i can get a campag mirage for <£30 and the ringa I have been looking at are 110 BCD and they are between £20 - £40 each, plus the campag will be a nice upgrade. New chain is not an issue as I would have to buy one either way.

I do have short legs so I may be better of with the shorter cranks.

The frame is a 50cm, and I was told tonight that my hips are rocking so I still need to drop the seat a bit.

PeeDee

165 used to be pretty standard in the old days. Nowardays the trend is for longer cranks like 170. If you have short legs then go for 165s if they are available, but if they aren't then 170s will work OK. Its only 5mm after all, not worth losing too much sleep over it.

BTW, have you checked that the chainset matches your bottom bracket? e.g. are they both squre taper (or whatever, doesn't matter so long as they are both the same)

You will also need to buy a special tool to remove the crank arms (though maybe you know this already).

retrobike007

PeeDee wrote:

165 used to be pretty standard in the old days. Nowardays the trend is for longer cranks like 170. If you have short legs then go for 165s if they are available, but if they aren't then 170s will work OK. Its only 5mm after all, not worth losing too much sleep over it.

BTW, have you checked that the chainset matches your bottom bracket? e.g. are they both squre taper (or whatever, doesn't matter so long as they are both the same)

You will also need to buy a special tool to remove the crank arms (though maybe you know this already).

I have the crank puller, and yes they are both square taper.

cougie

I dont think that crank length makes much difference to be honest.

why specifically a 53 chainring though ? what sprockets have you got there ?

retrobike007

25 - 11, my mate is running a 53 and when we get up to 30 mph he starts to leave me behind,

redddraggon

retrobike007 wrote:

Have bought a halfords road bike and I want to upgrade the front chainrings, as it has a 38/48, and I want 53, the cheapest way seems to be a new chainset. Campag mirage or similar, they all seem to have different arm lengths, whst the difference in the arm lengths?

retrobike007 wrote:

PeeDee wrote:

BTW cranks usually range from about 160mm to 175mm. Basically, the longer your legs the longer your crank. Having said that, its really down to personal prefernece how long a crank you prefer.

Thats more like the info I was looking for.

You say you want to upgrade the chainrings and the cheapest way will be to CHANGE THE CHAINRINGS>

retrobike007 wrote:

I have the crank puller, and yes they are both square taper.

They'll be a different square taper though I expect.

retrobike007

Why will the square taper be different, surely they are all the same?

Price for a Campag Mirage chain set is £28 + £7 Postage

Price for a 110 bcd 53 tooth £29.99
Price for a 110 bcd 39 tooth £29.99

£29.99+£29.99 = more than £35 for the Mirage set. :roll:

redddraggon

JIS and ISO are different Square Tapers.

And you can get chainrings way cheaper than the £60 you say. It'll definitely work out cheaper by the time you factor in the new BB you'll need.

Ben6899

retrobike007 wrote:

Why will the square taper be different, surely they are all the same?

No.

retrobike007 wrote:

Price for a Campag Mirage chain set is £28 + £7 Postage

Price for a 110 bcd 53 tooth £29.99
Price for a 110 bcd 39 tooth £29.99

£29.99+£29.99 = more than £35 for the Mirage set. :roll:

I thought you just wanted to increase the teeth number of the big ring?

£29.99 110bcd 53 ring < £35 Mirage chainset = same outcome.

Weejie54

The taper will be the same (same angle) but length of tapered section could be different.

http://www.sheldonbrown.com/bbtaper.html

Saves a lot of time.

retrobike007

Ben6899 wrote:

I thought you just wanted to increase the teeth number of the big ring?

Originally yes, but when I saw the full chainset was so cheap I figured I would just change the whole lot.

Ben6899

retrobike007 wrote:

Ben6899 wrote:

I thought you just wanted to increase the teeth number of the big ring?

Originally yes, but when I saw the full chainset was so cheap I figured I would just change the whole lot.

Fair enough, though I'd still search around for cheaper than £29.99 x 2.

retrobike007

110 BCD seems be a weird size, only a few on ebay, and they seem expensive for ebay prices.

Weejie54

110 BCD seems be a weird size, only a few on ebay, and they seem expensive for ebay prices

Because 53t at 110 BCD makes for a wee bit too much flex. 110 BCD is for MTB or compact chainsets. 53t is obtainable but not so common.

redddraggon

Spa Cycles is the place for chainrings

mostly harmless

What reddraggon said

http://www.spacycles.co.uk/products.php ... b0s149p293

retrobike007

Still £40 for 1 outer ring.

Weejie54

Cheapest 53t ring on Spa with 110 BCD is the Stronglight Zicral at £30 plus £3 carriage.
If you don't mind a steel inner ring (and 175mm cranks), you would be better off with the Mirage which Ribble have in stock for £26.45 plus £2.95 carriage (cheaper if you are spending £50 (£22.48 and free carriage) In fact, even cheaper without the Camapagnolo crankbolts £19.45 plus carriage (or £16.53 if you spend £50) - Many would be put off by the steel chainring - and Mirage isn't the cutting edge, finish-wise. You will have the advantage of 135 BCD which would mean a stiffer ring and the option of changing the steel ring at a later date.

retrobike007

I think thats the way to go.

I will go for the mirage, I am sure I can get my order up to £50.

Not sure on the campag range, how does it work? best and worst ?

Is Mirage the bottom of the range?

Weejie54

Mirage is right down there but all Campy stuff works.

Stumbling block may be the BB axle length (Mirage should be 111mm). Watch the chainline - if your current BB is for Shimano your chainset may sit out too far - even if the axle length is right..

retrobike007

Weejie54 wrote:

Mirage is right down there but all Campy stuff works.

Stumbling block may be the BB axle length (Mirage should be 111mm). Watch the chainline - if your current BB is for Shimano your chainset may sit out too far - even if the axle length is right..

Oh, can this be corrected by adjustment?

or should I be looking at this

http://www.ribblecycles.co.uk/sp/road-t ... HIMCHAR460

Instead

Weejie54

The first thing would be to measure the length of your current axle. It might not suit the Tiagra chainset either [it won't - see edit]. Campy chainsets will fit Japanese spindles but don't go on as far as Japanese style (JIS) cranksets. The bigger potential problem is fitting Japanese style cranks to ISO (Campy fit) spindles. They can bottom out (not happened in my experience - but frequent removal and refit can cause it).
If price is important, you may find it cheaper to go for the Mirage chainset and a new BB to suit it. It's really up to you. The link I gave earlier explains it better:
http://www.sheldonbrown.com/bbtaper.html

Edit - The set you linked to is a HollowTech chainset - it would need BB cups too

I didn't look at it closely enough earlier.

It would be quite an upgrade - but a lot more costly.

White Line

retrobike007 wrote:

25 - 11, my mate is running a 53 and when we get up to 30 mph he starts to leave me behind,

Pedal faster.

Best to get a new crankset if it's cheaper, as it seems that your choice of 53T chainrings with a 110BCD is fairly limited.

retrobike007

I think I will go for the tiagra and fit the hollow tech BB, I have the tools, as I have a hollow BB on my MTB

The hollow tech should be lighter and more reliable if the one on my MTB is anything to go by.