Author Topic: Centrelock or Iso disc, which to choose?  (Read 627 times)

Centrelock or Iso disc, which to choose?
« on: February 23, 2019, 09:29:17 am »
Having now got a pair of disc calipers that will go onto iso-postmount adapters I am converting the unused vtt frame to 650b (for purely ideological reasons  :demon:). I have a pair of 32h rims coming, the Alfine8 is 32h but I don't have a 32h front hub, my existing disc front wheel is 36h (when I built it I had a couple of spare 36h 26" rims and no Alfine hub). So I will have to get a new 32h disc hub. Before anyone asks the Alfine is nutted, everything else is q/r.

The Alfine is centrelock, the existing front hub is iso. Do I get a new iso hub to reuse the existing front disc? Or a centrelock hub to match the rear (which means buying a new disc)? If I go back to a derailleur on this bike I already have 32h iso rear hubs (only a consideration at present if I bork the Alfine).

Just for the looks of the thing I would consider also taking the disc off to use the wheel in a non-disc road frame (which might favour centrelock on aesthetic grounds).

What does the panel think?

Re: Centrelock or Iso disc, which to choose?
« Reply #1 on: February 23, 2019, 10:12:28 am »
there is a small practical benefit in using the same discs front and rear in that you might feel OK about using a thinnish rear disc but not a similarly  worn  front disc.  However this is lost if the discs are a different size/fitting anyway.

The decision is partly influenced by hub availability; you have to have a CL fitting on the alfine hub, no choice. Weirdly there is probably more choice in front hubs with CL fittings than six-bolt. Doesn't stop you from running six-bolt discs though, using an adaptor.  If you plan to wear out more than two or three discs the adaptor will pay for itself, because six bolt discs are cheaper to buy.

If I was after the lowest weight I think (expensive, not very long lived) CL discs with an aluminium lockring may just edge it.  But otherwise six-bolt discs are arguably a more practical choice.  FWIW it seems to me that sandwich construction CL discs don't last as long as solid ones; it might be that the stainless steel has to be  a slightly different grade to allow the bonding of the sandwich, but these discs start at about 1.75mm and the permitted wear limit is 1.5mm; this is just 0.125mm worn off each side.

cheers

Cudzoziemiec

  • Solar powered, tea fuelled cycle-wol
Re: Centrelock or Iso disc, which to choose?
« Reply #2 on: February 23, 2019, 10:25:22 am »
I'm not sure if a disc hub with the disc removed will look particularly "aesthetic" whatever type it is, so I wouldn't let that be a consideration. I have centrelock front and six-bolt rear, it doesn't cause any problems in practice and was down to hub availability at the time. Go with what you've got.
sideways bounding monkey lounging under fruit tree

Re: Centrelock or Iso disc, which to choose?
« Reply #3 on: February 23, 2019, 12:12:27 pm »
unused CL hub mounts can have a rubber cover over them; in practice this is so unobtrusive (esp on a black coloured hub) that you would hardly notice that it is a disc hub, unless the dish of the wheel is changed.  The dish remains the same with most IGHs and some hub generators (those with narrow spaced flanges) whether there is a disc mount or not.

cheers

quixoticgeek

  • Mostly Harmless
Re: Centrelock or Iso disc, which to choose?
« Reply #4 on: February 23, 2019, 08:06:11 pm »

I have a set of wheels with 6 bolt, and 3 sets with centre lock. The annoyance of the two standards is that I need to keep a stock of 2 different types of rotor, rather than having a single pair of spares that I can use everywhere. But within a wheel set, I do like front and rear to be the same, so I can swap them round if need be.

One thing to be aware of, some of the cheaper rotors are listed as not suitable for sintered pads.

But ultimately I don't think there is any major difference in performance between the two, and it really comes down to what hub you want to use as to which it comes with.

YMMV

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Centrelock or Iso disc, which to choose?
« Reply #5 on: February 23, 2019, 08:23:48 pm »
You can get 6 bolt to centre lock adapters.

Re: Centrelock or Iso disc, which to choose?
« Reply #6 on: February 23, 2019, 08:35:13 pm »
The lock ring on centre lock adapters covers the bolt heads, so the advantage I was hoping for (not needing a special tool) isn’t there.

I have some MTB wheels that use a 6 bolt unthreaded stud pattern with a centre lock-style lock ring that clamps on top, because apparently they couldn’t choose either.

QG: Is there a reason you keep spare rotors on hand?

quixoticgeek

  • Mostly Harmless
Re: Centrelock or Iso disc, which to choose?
« Reply #7 on: February 23, 2019, 08:42:31 pm »
QG: Is there a reason you keep spare rotors on hand?

Yes. I don't want to realise the day before a big ride that my rotors are too thin and need replacing, they are only about €16 each, and I tend to use them to hit the free postage threshold when buying other stuff.

I keep a chain, brake blocks, brake rotors, inner tubes, and outer tyres in stock, just in case. Right now I also have a cassette in stock as I know that I will replace the cassette when next I replace a chain. I also have new bars and new bar tape, as I damaged the bars on the ice in December, but I'm waiting for the ice risk to be essentially zero (so end of March), to do the swap. Spare cables live on the bike in the bike bag. I have a view that I should always be able to just get on the bike and ride so like to be prepared for common consumables. I'll probably be ordering chain rings in the next couple of months so I have them in stock ready too.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Kim

  • Timelord
Re: Centrelock or Iso disc, which to choose?
« Reply #8 on: February 23, 2019, 09:22:19 pm »
My take on it is:  ISO if you're going to use a disc brake.  Centerlock if you're forced to by hub choice (eg. SON), or to future-proof a rim-braked wheel[1], and you're probably still better off using an ISO rotor and anna daptor if you've already got some ISO in your stable.  If you were being a weight weenie, you wouldn't have a disc brake in the first place.

There's a lot to be said for being able to remove the rotor using nothing more than the torx bit on your multitool.


[1] I discovered that one of my wheels has a centerlock hub some 7 years or so after I purchased it, and only then because I decided it might be a good idea to service the bearings (which were fine - it doesn't do a lot of miles).  The rubber cover is that un-obvious.
To ride the Windcheetah, first, you must embrace the cantilever...

Re: Centrelock or Iso disc, which to choose?
« Reply #9 on: February 24, 2019, 08:29:19 pm »
My take on it is:  ISO if you're going to use a disc brake.  Centerlock if you're forced to by hub choice (eg. SON), or to future-proof a rim-braked wheel[1], and you're probably still better off using an ISO rotor and anna daptor if you've already got some ISO in your stable.  If you were being a weight weenie, you wouldn't have a disc brake in the first place.

There's a lot to be said for being able to remove the rotor using nothing more than the torx bit on your multitool.


[1] I discovered that one of my wheels has a centerlock hub some 7 years or so after I purchased it, and only then because I decided it might be a good idea to service the bearings (which were fine - it doesn't do a lot of miles).  The rubber cover is that un-obvious.

Yes, now that I have bought a disc for the Alfine I too have come to the conclusion that ISO is better if only because the discs appear to be cheaper and thicker (and rather less hole). There are some hubs that have small flanges and look a bit less obviously clunky so any aesthetic consideration will be minor. Obviously weight weanie is not a term to be used in the same breath as converted mtb and Alfine IGH, discs or no!

However I started fitting the bike back together this afternoon and came up with a new consideration. The fork I will be using is a Fireeye Stoker which is a fairly massive steel rigid fork, destined for bike parks and now discontinued because stunters in bike parks managed to break them. It has a steel ISO bracket welded onto very large diameter fork legs (34mm IIRC although they may be larger). The Post mount adapter goes on and clears the disc but only just - new pads in the caliper might just give me adjustment problems. Is there any difference in disc position between the various systems or indeed between various models of hub? I could do with something that mounted the disc a bit further inboard. It may be of course that it is Fireeye's cock up with the standard dimensions and there is nothing to be done. My existing front hub is a large flange entry level Deore. (I am just fitting the 26" wheels at present to get it all together and to see where the problems might be - the new rims come this week but I haven't got round to working out spoke lengths yet)

Cudzoziemiec

  • Solar powered, tea fuelled cycle-wol
Re: Centrelock or Iso disc, which to choose?
« Reply #10 on: February 24, 2019, 08:38:00 pm »
Interesting observation that six-bolt rotors tend to be thicker. I hadn't noticed that, but then I hadn't really compared them.
sideways bounding monkey lounging under fruit tree

Re: Centrelock or Iso disc, which to choose?
« Reply #11 on: February 24, 2019, 09:25:50 pm »

However I started fitting the bike back together this afternoon and came up with a new consideration. The fork I will be using is a Fireeye Stoker which is a fairly massive steel rigid fork, destined for bike parks and now discontinued because stunters in bike parks managed to break them. It has a steel ISO bracket welded onto very large diameter fork legs (34mm IIRC although they may be larger). The Post mount adapter goes on and clears the disc but only just - new pads in the caliper might just give me adjustment problems. Is there any difference in disc position between the various systems or indeed between various models of hub? I could do with something that mounted the disc a bit further inboard. It may be of course that it is Fireeye's cock up with the standard dimensions and there is nothing to be done. My existing front hub is a large flange entry level Deore. (I am just fitting the 26" wheels at present to get it all together and to see where the problems might be - the new rims come this week but I haven't got round to working out spoke lengths yet)

The idea is that the various disc systems give about the same lateral offset to the disc, but it doesn't always work out as intended. With a deore hub you can alter the hub/disc spacing slightly by playing around with the washers between the locknuts and the cones; this allows you to push the disc rightwards (whereas spacers on the six-bolt disc itself only let you push the disc leftwards).

cheers

Re: Centrelock or Iso disc, which to choose?
« Reply #12 on: February 24, 2019, 11:39:51 pm »

However I started fitting the bike back together this afternoon and came up with a new consideration. The fork I will be using is a Fireeye Stoker which is a fairly massive steel rigid fork, destined for bike parks and now discontinued because stunters in bike parks managed to break them. It has a steel ISO bracket welded onto very large diameter fork legs (34mm IIRC although they may be larger). The Post mount adapter goes on and clears the disc but only just - new pads in the caliper might just give me adjustment problems. Is there any difference in disc position between the various systems or indeed between various models of hub? I could do with something that mounted the disc a bit further inboard. It may be of course that it is Fireeye's cock up with the standard dimensions and there is nothing to be done. My existing front hub is a large flange entry level Deore. (I am just fitting the 26" wheels at present to get it all together and to see where the problems might be - the new rims come this week but I haven't got round to working out spoke lengths yet)

The idea is that the various disc systems give about the same lateral offset to the disc, but it doesn't always work out as intended. With a deore hub you can alter the hub/disc spacing slightly by playing around with the washers between the locknuts and the cones; this allows you to push the disc rightwards (whereas spacers on the six-bolt disc itself only let you push the disc leftwards).

cheers

Thanks Brucey. I think you have just answered my original question as well. It looks like another entry level Deore ISO fitting front hub will be favourite. Now I can have a play with this one to learn what to do and how to do it.

Thank you everyone. That was very helpful to clarify my thoughts.  :)