New Cranks needed - advice please!!

crazy88

Hello,

I am looking for some advice please, and I am new to cycling so haven't got my head around cranks yet.


A while back when cycling home I felt like my foot was slipping on the pedal. When i looked down I saw that one of my cranks (Left if looking down, without the chainrings on it) was about to fall out. I one-foot cycled a little bit more to get off the main road, and just as I did the crank cap fell out. Luckily I was about 200m from home at this point, so just got off to push it.

The offending part, a truvatic crank on my GT aggressor.



I tightened it, and didn't think too much of it, but the next day the same happened. As it happens, I then was in the process of buying a cheap road bike off a mate for commuting and didn't ride the mtb much. Anyway, my crank still keeps coming loose, so I must have stretched (correct word?) the thread? Would this be correct?

So, I need new cranks I believe. Any advice for cheap(ish) cranks? I don't really want to pay more than £50 max. Is it possible to buy anything decent for this price range? I saw the shimano alvivo on chainreactioncycles for 26 but then read that they were pretty poo. Still looking around so may post up others for opinions, but also would love some ideas as to good ones.

Other than the crank length and number or teeth (correct terminology? ha) is there anything else I need to measure to make sure I get the correct sizes etc?

Thanks in advance!!!!

duron1

You should not need new cranks. As long as the spline on the crank arm is not damaged then clean then up, slighty grease the bb shaft and use a new crank bolt and threadlock. Tighten to 38nm or as tight as possible without over doing it. Should be ok. Check after a short ride.

crazy88

Thanks for the reply!

I've tightened the cranks numerous times now and each ride they loosen and begin to fall off. Also, even when tight there feels like there is a slight clicking almost, which I suspected was due to a stretch?!

Stuy-b

this is a very common problem with square taper cranks, the first time it came loose and you kept riding it you have rounded the flats off allowing movement between the crank the the bottom bracket axle. no matter how much you tighten the crank bolt it WILL keep coming loose.
however all is not lost, truvativ do just sell left hand cranks arms for not much money at all.

http://www.jejamescycles.co.uk/truvativ ... 95791.html

crazy88

WOW! Thanks dude!!!!

I thought that I must have damaged it, as it's hapening all the time still as you say.

Just a quick question though, is it worth upgrading my chainset? Would I need a new bottom bracket that is not square taper? Or should I do this quick fix and change it all later? ha

Thanks again, really appreciate it. And can hopefully commute on this again rather than my road bike which is just too dodgy in this weather.

Stuy-b

for £58 you can have a massive upgrade to
http://www.chainreactioncycles.com/Mode ... elID=40496
these come with a new bottom bracket and wont ever have problems with loosening.
like i said the deore are a BIG upgrade from your truvativ.

crazy88

I had actually looked at that chainset as my rear mech is Deore too, so thought it might be a nice little upgrade. However, I know nothing about removing the BB. Will i need a special tool? Is it easy enough? I'd say I am fairly competant with these kinds of things, just not bikes.

Thanks!

Stuy-b

where you based? i have all the tools and what not and dont mind helping out a fellow cyclist

crazy88

Yorkshire, huddersfield to be exact. I bet you're down south...everyone on forums seems to be, ha!

If you are miles away, any advice on tools needed? I don't mind buying the right tool for the job as no doubt it will help sooner or later

duron1

If your aggressor has a deore mech you must have a xc 2 which is not square taper, I'm a Halfords Bikehut manager and know a xc2 uses a small splined axle. Don't use the same bolt again, must use a new one else it will come loose.

crazy88

It is indeed an XC2, and yes it was a halfords. I am going to remove the crank now for verification, ha! Not that I don't believe you, just that before this thread I had no idea there were even any variations lol.

Is the crank arm still damaged then you think, or just the bolt? And would the shimano deore mentioned above be a good replacement? Would it all fit etc?

Thanks!

duron1

It should be a spline about 10mm long and then turns smooth as it goes into the frame. The crank arm when tight should butt up to this. If the splines are on the BB, which they usually are then you just need a new crank arm. The axle is steel and the arm is Alu so rounds off easily. The new Deore crankset would suit the bike will with your already matching deore mechs and shiftera. You will probably find that it shifts slightly smoother too.

crazy88

Here is a quick, but dodgy, pic I just took of the crank. You were right, it is indeed a spline, and not square.



I am very tempted to purchase the deore one, as hopefully it will be better. What tool would I need to remove my BB and put the new one in?

Thanks

nicklouse

have read of Park tools.

if the deore you are looking at is HT2 you will need the BB shell faced. LBS job.

yours is it 12 splines? then it is Power spline. treat as square taper on the Park tools site.

10 splines? ISIS.

crazy88

ok, I get that the HT2 is hollowtech2, and yes the deore one is HT2. But I am completely confused by "you will need the BB shell faced. LBS job"

Mine is 12 splines too, so will I need two seperate tools, one to remove current BB, and one for new BB?

I am reading through park tool, but a lot of it feels like a different language, haha

Thanks for advice!

EDIT: Think I know what you mean by shell faced now, so will enquire about good LBS' near me. Have not used any yet, so no idea!

Just on the hunt now for a tool to remove current BB. Thanks again!

EDIT 2: Just to be awkward, is it worth getting a different chainset which doesn't require the BB shell faced? I have just been reading about it, and from what I read it seems to be chalk and cheese as to whether people like the HT2!

I'm open to suggesitions.

nicklouse

facing info here
http://www.bikeradar.com/forum/viewtopic.php?t=12654663

the HT2 is one of the better External designs.

and Deore is at a good price point.

leaflite

Is that totally necessary? I've just fitted a deore chainset to the apollo and I only needed a shimano tool that looked like a huge spanner to tighten the bb-nothing else

nicklouse

do you want the bearings to last?

did you read the fitting instructions?

EVERY bike I build has the tool applied even if it is just to check it has been done.

When we have a bike back it with worn BB early I check to see if it has been faced. normally it has not been.

crazy88

Would a LBS be happy with me purchasing the chainset online and then taking it for them to fit? Or, should I just buy one from them? I have no relationship with a LBS, but would be handy if i did as I have started to cycle quite a bit recently.

Either that, or as mentioned I find a different chainset with an easier BB.

Thanks

thel33ter

crazy88 wrote:

Would a LBS be happy with me purchasing the chainset online and then taking it for them to fit? Or, should I just buy one from them? I have no relationship with a LBS, but would be handy if i did as I have started to cycle quite a bit recently.

Either that, or as mentioned I find a different chainset with an easier BB.

Thanks

I got one my Deore from CRC, and the local 'Action Bikes' did a great job sawing the old cranks off :shock: and fitted the new ones for £25. I could have bought all the tools, but I didn't think I would use them very often so I got the shop to do it. Evans quoted £60 just to get the old ones off BTW

Northwind

Can't tell for sure from the pic but that looks like a Powerspline, if it is, I've got a set kicking around the garage somewhere, you'd be welcome to it, never likely to put it into another bike. Looks like it'll cost about a tenner to post if you want it but might be a wee while before I can post.

They are s**t cranks though and I'd recommend an upgrade myself. Heavy, flexy, and terrible bottom brackets

Nachimir

crazy88 wrote:

Would a LBS be happy with me purchasing the chainset online and then taking it for them to fit?

Entirely your prerogative where you buy from, and I'm sure any sane LBS would be glad to take on work. Several of the guys from my LBS have said to me they used to buy online before they got staff discount.

crazy88

Thanks for the replies!

I think I am going to go with the Shimano Deore cranks. Going to ring around a few places tomorrow for quotes to get it shell faced, but i'm still thinking about buying the other tools required and fitting myself for learning reasons...is this wise or just madness?

Oh, and Northwind, thanks for the offer, but I'm gonna buy some new ones anyway

Northwind

No worries, that's what I'd do too I don't give away good stuff!

crazy88

hahaha! Fair point!!!!

I will report back on what the LBS's say. I haven't used any around here though, so no idea whether any are good or not.

If anyone is local to Huddefsfield, by all means let me know of any good ones

crazy88

Well, after the busy christmas period and all the other bumf that goes on with that i finally got my BB faced and tapped, and I fitted my new chainset! Wahooooooo

Here's a pic, excuse the quality as it's a phone pic.



Have yet to ride it (only fitted late sunday night, and been busy with work and decorating since). A few mates and i have a ride planned for the weekend, so well excited for that!

Thanks for all the advice in the thread.

plodtv

yeah, I had this exact same problem with an aggressor and bought same chainset as you to replace it. It served me very well for over a twelve months and still going strong (though I have upgraded to a bouncer! )

crazy88

Ah, nice to know someone else in the same situation. I am hoping this one will last me a little longer. I understand I maybe made it worse by riding it when loose, but it has only lasted less than 100 miles, so not exactly good.

I have high hopes for the Deore though.

I just need to get my gears correctly index'd tonight as i'm out on it at the weekend and the shifting is terrible at the moment.