Wednesday, 8 January 2014

AbsoluteBlack single ring set up

I used to run a single ring, with guards, in the 1990s. I liked the simplicity of concept, it reduced weight a bit but more importantly it helped a bit with clogging. But since then I haven't really bothered to set one up again, mainly as the guards always seemed to rub with the chainline being difficult to set up. Modern re-inventions tended to involve chainkeepers attached to the seat stay, rather than the simple traditional double guard I used to use, and so lost the advantage of getting rid of a front-mech like object, neatly positioned around the bottom bracket area to successfully collect mud and vegetation.

It was with interest then, that I received a test 38 tooth ring (via Dave Haygarth) from Marcin at AbsoluteBlack. This ring differed from stuff I had seen previously, borrowing from the growing mtb market for single rings, and featuring a cleverly milled ring that requires no guard, chainkeeper or any other device to make it stick on. I was initially skeptical but equally hopeful that this could be the ideal solution to dealing with super muddy conditions later on in the 'cross season.




Matched to my On One Pickenflick and it's huge mud clearance, I've been running the ring in training and racing and can now report back. Set up is key to getting this ring to work. It's not hard, it just needs to be done right. Chain tension as well as the teeth profile is what keeps the chain on through the rough and the boggy, and chain length needs to be optimised to gain maximum advantage from the ring. Successfully installed, with clear instructions from AbsoluteBlack, the initial feel through the pedals was instantly positive. Maybe you don't pay too much attention to how your chain feels as you pedal, as opposed to your legs, but I could feel a smoothness that wasn't present on my perfectly good double chainset set ups.

The ring has now done a variety of races, and training sessions and in a variety of conditions and has passed all tests with flying colours. Bumpy tracks don't faze it - it hasn't been possible to bounce it off, though me and Dave have tried hard. It's trained and raced in thin sloppy mud, sticky mud (Bradford) and Todmorden (ie biblically thick) mud and simply kept on going. In many hours of use, I had one small problem at Todmorden Cross when a large, ripped up clod of soil got under the chain and onto the ring and caused the chain to fall off. But, and here is the crucial bit, it was super easy to get back on - no jamming on a chaincatcher, no falling between ring and bottom bracket and sticking, just an easy flick to get back on. Over the period of use and in the conditions I rode it in, I would have expected to drop a chain or have problems on a double set at some point anyway. No system is perfect, but the AbsoluteBlack ring works as well, if not better than anything else I've used.

Pic: Dave Haygarth

As I indicated earlier, the main advantage for me of a single ring is reduced clogging and this positive effect has been clearcut. No bike is clog free, and even if the frame keeps free then the cassette can often stop working properly anyway. But, the AbsoluteBlack ring set up and the resulting simplicity around the bottom bracket area has markedly reduced mud and vegetation build and kept the bike not only trouble free, but weighing less as a result too. Paired with an 11-28 block (10 speed chain, Sram Red rear mech), my 38 tooth ring gives me all the gears I had before and I have never missed the potentially wider range of gears a more traditional double set up gives. From now on, I'll be running this setup on my Pickenflick during the winter season and for me it's a perfect solution to the increasing levels of mud our climate seems to bring u.

UPDATE Jan 14:

I rode the last NWCCA race of the season recdently, starting on my bike with the single ring on. To my surprise, I had a couple of problems with the ring, dropping the chain on both occasions. After consultation with Marcin from absoluteBlack and some careful analysis of my actions and course conditions at the time, I feel fairly confident I've pinpointed the problem.

In essence, both 'drops' were caused by my very rapid changing of gear up the block on transitions from bumpy descent to slow grinding section. According to Marcin, changing 3 or 4 cogs in one movement will result in instability for any chain (on a single ring or otherwise). Ally that to a bumpy section, with no chain guard or front mech to hold the chain on and you have the problem. The solution, a technique which he maintains pro mountain bikers have been following for years, is to shift one cog at a time, rather than the multiple cog, rapid shifts that I was doing. The concession for this is that it takes a little forward planning so as to avoid rapid dumping up the block as the speed slows down. Marcin maintains also that the mtb testers for his single ring have not dropped the chain in testing due to their attention to this technique and that he often finds cyclocross riders are a bit 'gung ho' in shifting technique and could do with refining their actions. Certainly, I have never dropped the chain in thick mud, nor even on a descent - the 3 times I have had a problem have ALL followed multiple shifting into an easier gear before a slow boggy section.

UPDATE 2 Feb 14:

 After some discussions with Marcin from absoluteBlack, it's important to point out that the spring tension on Shimano mechs needs optimising to make the ring work to the best of its capability. Here's what it says on the absoluteBlack website....

Important information for SHIMANO derrailleur users:

In order to get best results we recommend increasing cage return spring tension. New derailleurs are assembled with the spring in the mount that allows the most relaxed position of the spring. However there is another position on the cage which will increase that tension. It is a standard procedure, please navigate to point no.7 in the link. You may also ask your LBS to do it for you.

Sram users are not required to do that as oem springs are already in high tension position.




If you missed it, here's Dave's recent video too:


12 comments:

Dave said...

Nice piece. This is the ultimate single setup as used by Adam Craig with the only draw back is possibly the price, not particularly absoluteBlack but SRAM versions too. After running single old style with double chainguards for quite sometime with no pit crew or spare bike by the end of a race there would be a build up of mud between the guards getting under the chain. currently running an interim setup of a single guard, single ring and a dogtooth chain watcher whilst saving up some pennies

Gavin Thomas said...

Are you using a mtb crankset with the 38t ring or a road (110 or 130bcd)

I'm looking at this frame for racing and want to run a 42 ring with 11-32 out back and wondering if it will fit

crossjunkie said...

I'm using a 130bcd road crankset with the ring in the outer position.

You could use a 42 and 11-32 but would need a chainguard/keeper of some sort as the 32 cassette means you would likely need a long cage mech, With a long cage mech, the chain tension is insufficient to keep the chain from bouncing, a problem you don't have with short cage.

Gavin Thomas said...

Wow. quick response

Did you say and SRAM crank won't work because of the length?

Perhaps a rethink and go with a 38 on a mtb cassette.

How do you find it for racing? Muc clearance on my kinesis with v brakes and travel agents is a bit poor.

Gavin Thomas said...

I thought i could use a medium cage with an 11-32?

( a 9 speed xt mech will apparently work with 10 speed shimano road shifters)

crossjunkie said...

SRAM cranks are no problem with a single ring. As long as the ring is in the outer position on the crank arm, nothing will foul the chainstay.

A medium cage will indeed work but with most single rings (incl absoluteBlack) will still have more chain slap and hence insufficient chain tension to keep the chain on without an extra keeper like this http://www.paulcomp.com/chainkeeperextension.html

I found a 38 ring with a 28 rear cassette perfect for normal cx - you are usually better off running if you need an easier gear than that in a 1 hour cx. Power monsters can get away with a 42 instead and the same 28 at the back. So, if you are looking at a pure cx set up, ditch the med/long cage mech which I personally find more at risk of ripping off in deep claggy conditions and go for a 38x28 set up It should provide all the gears you need. In addition, 38x12 (let alone 11) is as big as you need for a cx race in normal UK conditions.

Clearance for the single ring or the Pickenflick? Single rings are much cleaner, especially if you don't add a keeper device and on the P'flick, clearance is WAAY better than on a canti Kinesis - nice bikes but my mates used to clog quite a bit at the back in comparison to a disc equipped Pickenflick :-)

Gavin Thomas said...

Excellent reply! thanks. 38 sound sensible and means I can use my SRAM force chainset using the outer

I just thought planet x were stating you can't use road cranks because of clearance (or is this because of a 50 or 53 chainring)

Thanks for all the info.

Get well soon BTW!

crossjunkie said...

Cheers, getting there now :-)

The clearance issue is for larger inner chainrings on the chainstay, not the crank arm. I'm not aware of any clearance issues at all with crank arms and have used Ultegra and FSA Gossamer myself without issue.

James Britton said...

Great post.. I'm building a cx bike now and love the idea of single chainring... Seems your set up is very similar to the cx1 set up but you use a standard red rear mech. I'm considering following the same but the sram cx1 mech according the sram website prevents chain slap.. It is also £160 which is a lot when I seem to replace the rear mech a couple of times a season. Based on your experience it seems a standard force rear mech will work fine as long as I don't want to go any higher than 28 on the rear cassette. I then save myself £90 on the rear mech...

Would you agree? Do you see the need for the extra features of the cx1 rear mech with a 11 28 cassette?

crossjunkie said...

As far as I know the spring tension on a Force mech is the same as a Red mech. Therefore it should work as well. The Red mech has enough tension to work, despite not having a clutch like the cx1 mech. But, you have to shift sequentially and not 'dump shift' to avoid dropping on descents. Once you learn the technique it's fine. If you are worried, you can always get a 2nd hand clutched SRAM mech eg XO or XX which should still be cheaper, but I like the short cage performance with a 28, rather than a mid cage mech which can flap more and risks damage in vegetation and mud. Hope that helps - do ask more questions if needed :-)

James Britton said...

Thanks helps to have some context.. Pretty sure I dump shift quite a lot.. In our league (western league) I can think of a few courses where you go from full speed to brake and then sharp ascent which means shifting down (up block)... I think I'm going to go with force shifters and mech and then test it.. If I do find it drops because I dump shift then I'll just bite the bullet and buy a cx1 rear mech. By then I'll have saved up enough money!

Hope the recovery is still going to plan...

Liam O'Connor said...

Just found this chat, very interesting stuff! Being a tight old wad I'm hoping to avoid buying the CX1 rear mech. So for cross racing I'm thinking of running a standard Force 22 rear mech with a CX1 crank and chainring coupled with a 11-28 Force cassette (11 speed) and a KMC chain. Does that sound feasible? Be interesting to hear any comments. Ta.