Before anyone says these forks are crap, yeah, I kinda know that now. I just fancied trying something light (and cheap) on my MTB which is mostly used on roads and towpaths 😥

I've installed a star nut on a set of suspension forks before with no drama but this brand new set of forks now have a 2" hairline crack at the top of the steerer.

I now have no intentions of using them and would like a refund. I am about to get onto CC so what do you reckon their response will be???

seems a pretty straightforward warranty replacement IMO.

Could easily be a manufacturing defect in a cheap fork.

Why not give them a chance to respond first then come back with the news?

if its carbon fibre steerer they might say you shouldn't have used a star nut. if its alu they might replace it.

What where the directions? Carbon steerer?

You only have the chance of a refund if there is a fault with the forks – not if you have been hamfisted. With a carbon steerer you shouldn't use a SFN

http://www.sheldonbrown.com/gloss_st-z.html

"Star nuts are only for use on metal steerers and should never be used on carbon steerers. Forks with carbon steerers generally come with special expansion plugs that serve the function of a star nut, without the sharp edges that might damage the fragile carbon steerer."

SFN in a carbon steerer = it's your fault.

There was a good troll thread by dan a few years back along these very lines.

If it's an Alu steerer then you prbably have a case.

Sorry guys, I forgot to say it was an ally steerer. The alloy seems much more flimsy/brittle than the Manitous they were meant to replace. I just wanted to know if I had a case as an ally steerer should be strong enough to accept a star nut.

To top it all off. I have 180mm front discs and the IS mount on these forks is for a 165mm. There was no mention of the optimum rotor size on the site so it didn't even cross my mind that there might be an issue. I had a spare +20mm adaptor so I tried that on and the rotor is obviously out by nearly 5mm. I dont want to upgrade to 185s as my brakes have just been serviced and I bought new rotors so I'm sticking with the 180s…

The Manitous are now back on the bike 😳

"the IS mount on these forks is for a 165mm"

I thought IS were pretty much all the same?

IS mount is for 160mm front isnt it?

Pass. I never realised IS means 165mm rotors. That is incidental – the issue is with the cracked steerer

well, talk them about the cracked steerer – unless it says 'don't use an SFN' you've got a good case.

IS mount is not for any specific size of rotor – it is an IS mount. You use different callipers for different size rotors or an adaptor.

If you were using a proper installation tool than you have a claim, if you were just 'whacking' it in then CC may not be so receptive.

The mounts must be for a 165mm rotor as they caliper was miles out when I used a +20mm adaptor?

To top it all off. I have 180mm front discs and the IS mount on these forks is for a 165mm. There was no mention of the optimum rotor size on the site so it didn't even cross my mind that there might be an issue.

If you have manitou they will be post mount (standard 160mm), and running a 180mm rotor will mean you already have some sort of adaptor fitted. To switch to IS (standard 160mm) will mean a different mount (not a +20) so i dont know what your doing to get an extra 5mm from nowhere.

Without meaning to sound rude i suggest you take all this stuff to a shop and get them to give you an opinion, rather than guesses on a forum. Unless you can post pics?

It's hard to reply to people directly without being able to 'quote' people like you can on other forums. The only way I could get the 180s to work with these forks would be by using a 15mm adaptor and I don't think such a thing exists.

I shall get on to CC and see what they say about the cracked steerer but i am not exactly brimming with confidence…

It's hard to reply to people directly without being able to 'quote' people like you can on other forums.

😉

Sorry!

Stato. I never claimed to be an expert on this subject but the calipers are out by 5mm when I tried to use the +20mm adaptor.

I'd like to thank everyone for their advice. I wasn't really looking for a bollocking and if CC say it was my fault then fair do's. 😕

The IS mount is not for any specific rotor diameter, the calliper (or calliper adapter when using post mount on an IS fitting fork) is what will determine the rotor size, precisely what brake/rotor/adaptor setup are you currently trying to use?
Considering these forks seem to be glass slipper delicate already are you sure you need more than a 160mm rotor?

As for the steerer splitting, assuming you fitted it correctly and didn’t get a bit too bashy with a lump hammer, I can’t imagine why they would refuse to replace, I’d have thought you’d have to go some to split a steerer tube fitting a SFN unless it is faulty to start with, perhaps try a head doctor or similar in the replacement fork?

I say it again – an IS mount is simply that – an IS mount – it is not for any specific size of disc – the disc size is dependent on the caliper or the adaptor.. all IS mounts are the same – there is only one specification of IS mount

I all forks were for 160mm rotors unles you buy a new adaptor & disc? same with frames?, exceptions being likes of boxxers or other long travel forks which may take a minimum of 180 or 203?

IS forks – the caliper dictates what size rotor you need. eg Hope do a 160mm, 180mm and 200mm caliper for front (same caliper will take a 20mm smaller rotor at the back). A +20 adapter allows say a 160mm IS caliper to fit a 180mm rotor.

Post mount (eg Manipoo unless old) bolts straight on a fork to take a 160mm rotor. If you want to fit a 180mm rotor then you need an adaptor to fit.

TandemJeremy

I know what you mean so it must be the way MPH calipers work out when you fit them to an IS mount. The rear rotors are 164mm (again this will have a lot to do with the mount – I don't know if that mount is standard IS before anyone asks)

The cracked steerer is the main issue and I can work around the braking problem…

crash test rider is right but so is tj and cookieaa. IS refers to the way in which the caliper or adaptor fits to the frame fork, its the International Standard, as opposed to the post mount method.

as a general rule, you can bolt an IS caliper straight on to an IS frame or fork if you are using a 160mm rotor. same for post mount frame and post mount caliper.

you can then use adaptors for both systems to run bigger rotors.

I have a Cannondale road bike which came with a star nut in the carbon steerer tube BTW

If you were using a proper installation tool

One of these, right?

MPH Callipers? As in Giants OEM brakes from a few years back which were essentially (I’m sure I’ll be corrected here) old style Hope C2/O2? If that’s the case then they used 185/165mm rotors didn’t they? Not 180mm….

Slowrider

The Manitous were post mount and these forks are IS. Can you think of a mount that would work in this. I tried a +20mm adaptor and it took the calipers almost 5mm further than the braking surface of the disc. I'd need a mount that didn't move the caliper out quite so far 😕

CrAsH…tEsT..RiDeR – Member
I all forks were for 160mm rotors unles you buy a new adaptor & disc? same with frames?, exceptions being likes of boxxers or other long travel forks which may take a minimum of 180 or 203?

Nope, all IS mount forks have a standard mount, end of, the calliper/adapter dictates rotor diameter hence some manufacturers offer 160 while others offer 165

The Boxxer mount is unique to that fork and means that like all rules there is an exception…

cookeaa

MPH 3 fronts are 180mm and rears are 164mm. I just bought some replacements and they are exactly the same…

MPH Callipers? As in Giants OEM brakes from a few years back which were essentially (I’m sure I’ll be corrected here) old style Hope C2/O2? If that’s the case then they used 185/165mm rotors didn’t they? Not 180mm….

yup, that's what I understood

the calipers are out by 5mm when I tried to use the +20mm adaptor.

Right, can we get a list of the parts your using please?

Manitou fork, which one?
Giant MHP brake, direct mount to the Manitou? or used an adaptor?
New forks, which ones, got a link?
what adaptor have you been using on this new fork? any model/part numbers?

Also, if its 5mm off at the rotor then its technically 10mm out based on rotor size (its based on diameter not radius)

Trail-Blazer – Member
Slowrider

The Manitous were post mount and these forks are IS. Can you think of a mount that would work in this. I tried a +20mm adaptor and it took the calipers almost 5mm further than the braking surface of the disc. I'd need a mount that didn't move the caliper out quite so far

Right specifics are required in order to help you:

Precisely which Calliper (manufacturer and model) do you have,?
Precisely what rotor are you trying to use?
Exactly which “+20” adapter did you buy?

Okay, so I think could get away with using a 164mm rotor on the front. That would kind of solve my problem. I don't really want to change the brakes on this bike…

Trail-Blazer – Member
Slowrider

The Manitous were post mount and these forks are IS. Can you think of a mount that would work in this. I tried a +20mm adaptor and it took the calipers almost 5mm further than the braking surface of the disc. I'd need a mount that didn't move the caliper out quite so far

Right specifics are required in order to help you:

Precisely which Calliper (manufacturer and model) do you have,?
Precisely what rotor are you trying to use?
Exactly which “+20” adapter did you buy?

Giant MPH 3

MPH 3 180mm rotor

A2Z IS to IS adaptor

The adaptor wasn't bought specifally for this project but I tried it on to see if it would work 😀

MPH 3 something like this?: http://www.wrower.pl/instrukcje/Giant/2001-MPH-3_owners_manual.pdf

Yes that's the one – the rotor pictured there is the 164mm rotor which they used on the rear…

section 2.4 is that the type of adatep you had for your manitou fork?

section 2.4 is that the type of adatep you had for your manitou fork?

If it is then the IS caliper is for a 165mm rotor, adding a +20 would make it work with a 185mm rotor. The dodgy giant post mount adaptor is whats throwing us here, most adaptors of this sort are +20 but the Giant one appears to be a +15 (if it makes your 165mm caliper works with a 180mm rotor)

Yes, definitely that one…