Search found 40 matches

by SIL4
25 Sep 2020, 11:23pm
Forum: Bikes & Bits – Technical section
Topic: 104 BCD 4 bolt 42t single ring recommendation
Replies: 9
Views: 381

Re: 104 BCD 4 bolt 42t single ring recommendation

Brucey wrote:sometimes you just can't square the circle and get a decent sized chainring in the right place for a 1x setup. In such cases you can end up choosing between a bad chainline, fewer gears (shorter cassette at wider chainline) or more chainrings. If you want low Q also..... well I think it is going to be a compromise.

cheers

Indeed, hence the query....it's an FC-T551 Deore trekking triple (48/36/26) c'set, 175m, 181m Q, 50mm chainline on a 68mm SM BB52 B/B (with spacers) with 15mm+ crank inner-stay outer clearance on both sides, 120mm chain stay width (outside-edges). I'd like a 42t, single ring, 50mm-ish chainline replacement with a lower Q of around 155-160mm that I know will fit before I order it but not an easy one to work out without a bunch of spare cranks to hand to try.
by SIL4
25 Sep 2020, 9:36pm
Forum: Bikes & Bits – Technical section
Topic: 104 BCD 4 bolt 42t single ring recommendation
Replies: 9
Views: 381

Re: 104 BCD 4 bolt 42t single ring recommendation

thelawnet wrote:https://amber-bikes.com/chainrings/104-bcd-chainring

Thanks, never seen that one before but will look investigate further.
by SIL4
25 Sep 2020, 9:36pm
Forum: Bikes & Bits – Technical section
Topic: 104 BCD 4 bolt 42t single ring recommendation
Replies: 9
Views: 381

Re: 104 BCD 4 bolt 42t single ring recommendation

Brucey wrote:unless 1x specific, modern derailleur chainrings have shortened teeth, gates, ramps etc which are specifically designed to help the chain shift, i.e. 'fall off'. If you use one such as a 1x then you should use a chain guide/FD to help keep the chain on.

It can be acceptable to use a singlespeed chainring in a 1x system, because the teeth are full-size. I have even filed the sides of 1/8" chainrings to make them compatible with 3/32" chain; the snugger the fit, the less likely the chain is to derail.

If you can't find suitable chainrings in 104mm BCD four bolt format, it would be best to use a different chainset instead, with a better choice of chainrings.

Surly do stainless chainrings (with full size teeth) in 104mm x 4 format, in 32-36T sizes.

Thorn do a 42T one

https://www.sjscycles.co.uk/chainrings/32-thorn-104mm-bcd-4-arm-reversible-single-chainring-332-inch-black/

NB some shimano 4-bolt 104 chainsets use a non-standard shoulder dimension in the middle position, which means that chainrings which fit the outer position can't be used in the middle position unless the chainset or the chainring are modified.

cheers

Thanks for that. It's either a new chainset or a new chainring. My preference would be to fit a suitable replacement road chainset with a lower Q to reduce the very high 181m Q factor of the existing Deore crank, but that might be too close to call in terms of clearing the stays (120mm across) without trial and error of trying different c'set/bb combinations, which I don't have lying around sadly (e.g. a 141m l/h Utegra crank just clears the stay, r/h set fouls it). The alternative is another MTB c'set swap, perhaps with a slightly reduced Q but they only tend to go down to 170m-ish at best. I run a wolf tooth single ring on my road bike which is great but finding a 42t 4 bolt in 104 is tough. I checked the Thorn site previously but missed that one so may well order one of those or the amber bikes one referenced below. cheers
by SIL4
25 Sep 2020, 6:05pm
Forum: Bikes & Bits – Technical section
Topic: 104 BCD 4 bolt 42t single ring recommendation
Replies: 9
Views: 381

104 BCD 4 bolt 42t single ring recommendation

I'm converting to 1x for winter and looking for a suitable 10 speed compatible, 104 BCD, 4 bolt, 42t single ring-specific to use in my Deore trekking 48-36-26 triple (middle ring position).

Have looked at usual (Raceface, Wolftooth etc.) and there seems little suitable but wondering if a Stronglight/TA equivalent would suffice?
by SIL4
19 Sep 2020, 9:59am
Forum: Bikes & Bits – Technical section
Topic: Cork handlebar tape
Replies: 4
Views: 361

Re: Cork handlebar tape

Cinelli - especially camouflage...
by SIL4
12 Sep 2020, 5:54pm
Forum: Bikes & Bits – Technical section
Topic: Low Q factor chain set replacement suggestions
Replies: 2
Views: 233

Low Q factor chain set replacement suggestions

Any help on this would be appreciated.

I have an as-new Dawes Gran Tour 725 26" tourer which I bought a few years back for some weekend touring but which laid unused after a long period working abroad. I had tried to sell it recently, rather than leave it unused but, after retiring my Ultegra-equipped BMC with a cracked frame, decided to keep the Dawes for use over winter while pondering whether I want a replacement road bike.

It uses a mix of old series Tiagra triple 4703 l/h STI with 4703 triple front mech, with a Deore trekking chainset (FC T551, 48/36/26, 175mm, 50mm chainline, 181mm Q factor on a BB52 63mm BB) with a Deore M771 rear mech and 10sp. 11-34 cassette.

It's a nice bike and I've been using it on flatish, Cambs roads and unladen, and not as a loaded tourer and probably wont. Two gripes are the gearing (front shifting is functional but very noisy and needs constant trimming, the 11 rear and 26 front ring and never used, and the big gaps at the top end of the cassette are too big) and the crank tread. After a few decent rides and miles, my knees and hips have been in agony and I suspect (from previous experience) that its the crank Q, which is quite different to my Ultregra (141mm). I've tried subtle adjustments to saddle, cleats etc. but it still feels alien and very uncomfortable.

There's at least 15mm clearance from inside of the cranks to the stays (picture below) and an Ultegra l/h arm will clear the stays by 3-5 mm (the r/h arm spider fouls the stay).

The simplest solution, without the expense of replacing shifters, mechs, BB etc. would be to find a lower Q but otherwise identical hollow tech-type crankset to simply replace the current one but other Shimano MTB (e.g. XT) chainset Q factor only seem to come in a few mm smaller (175mm). An alternative would be to perhaps swap out the rear cassette to a 12-30 and ditch the front mech and triple altogether to get rid of the noise and constant ring swapping and just replace to with a lower Q single 44ish ring or a double with a chainsaver inner ring but I know there might be issues with a road type crank not clearing the r/h stay but don't have them any spares hanging around to try.

Any suggestions would be appreciated.
by SIL4
2 Jul 2020, 4:37pm
Forum: Bikes & Bits – Technical section
Topic: BMC GF02 chainstay crack?
Replies: 7
Views: 539

Re: BMC GF02 chainstay crack?

Have been in touch with BMC directly so will see what they say...
by SIL4
2 Jul 2020, 2:46pm
Forum: Bikes & Bits – Technical section
Topic: BMC GF02 chainstay crack?
Replies: 7
Views: 539

Re: BMC GF02 chainstay crack?

Thanks for the responses - the bike was brought new abroad and frame is well out of warranty, and so it was really a call for any similar experience before getting the sand paper out..
by SIL4
1 Jul 2020, 7:13pm
Forum: Bikes & Bits – Technical section
Topic: BMC GF02 chainstay crack?
Replies: 7
Views: 539

BMC GF02 chainstay crack?

Any thoughts on this would be appreciated

I noticed today what looks like a longitudinal crack in the l/h chain stay of my 2015 BMC GF02 disc, aluminium frame: surface is slightly ridged and self-evidently crack-like. 1000s of road miles covered but never absued/crashed. Just wondering whether it's not as bad as it looks or a horrible failure just waiting to happen?

Don't want to scrap it but don't wish to end up in A&E either.
by SIL4
20 Aug 2017, 11:57am
Forum: Family Cycling
Topic: Help please in choosing a bike for an 8yr old
Replies: 9
Views: 1916

Re: Help please in choosing a bike for an 8yr old

Hi, have sent you a PM.
by SIL4
29 Feb 2012, 9:00pm
Forum: Bikes & Bits – Technical section
Topic: my next bike ... which one?
Replies: 9
Views: 1041

Re: my next bike ... which one?

Discounted 2011/12 Kona Sutra if you can get one - steel frame, racks, strong, fast. I have a 2005 model - brilliant. Best bike I've ever owned.
by SIL4
25 Sep 2010, 10:03pm
Forum: Off-road Cycling.
Topic: Cleland Cycles & Geoff Apps are back!!
Replies: 1
Views: 1075

Cleland Cycles & Geoff Apps are back!!

Geoff Apps, the proclaimed father of mountain biking and founder of Cleland Cycles, is back with a contemporary take on his classic Aventura, arguably the original ATB - and 29er.

True to the concept of the original, with all of the features of a Cleland intact - plus many more design innovations (check out the "swing" pedals) - the new good news is that Geoff is looking to put his "Aventura TT" (Twenty Ten") into production, with an initial limited potential run of 100 - and may be more, with further variations in the pipe.

His website gives a full run down of the latest Cleland, as well as providing a fascinating insight into how it all started - if you haven't seen it, check it out.

It won't appeal to the hardened down hiller, but the latest incarnation is pretty special and the closest I think there is to a truly built - for - Britain ATB with a twist.

I'm not affiliated to Cleland but just wanted to share this link, as it's possible to register now for interest in a pre-order...and me wants one!!

SIL4
http://clelandcycles.wordpress.com/bikes-1978-2010/
by SIL4
26 Nov 2009, 4:02pm
Forum: Bikes & Bits – Technical section
Topic: Disc brakes & Tektro RL 520 - modulators req?
Replies: 4
Views: 1441

Re: Disc brakes & Tektro RL 520 - modulators req?

Thanks for the replies. Mine has the MTB version BB7s connected to Avid's ownm MTB levers, so will go with the Tektro RL520s and see how it goes - they are described as linear pull, so should be fine with these if they also work with V brakes. And will fit a 9 speed bar con- control. "Monster crosser" here we come...
by SIL4
25 Nov 2009, 7:51pm
Forum: Bikes & Bits – Technical section
Topic: Disc brakes & Tektro RL 520 - modulators req?
Replies: 4
Views: 1441

Disc brakes & Tektro RL 520 - modulators req?

My 2005 Kona Sutra runs 105 STIs using standard cables to Avid BB5 discs.

This is the 2009 Kona Sutra which uses Tektro RL520 levers ('cos they replaced STIs with bar-end shifters) to Avid BB7 discs. If you look v. closely, it looks like there's a modulator integrated into the cable - or it might just be an adjuster: either way, I can't tell and can't find any reference to them! The Salsa Fargo sports the same lever-brake set up and has these in-cable "barrels" too - you can just see them Any ideas?! Nothing on the Avid website suggesting modulators are required so I am a bit stumped. Query arises because I want to convert my new flat barred Kona Unit 29er to drops with RL520 and bar ends and it uses BB7s too: it will look pretty much the same as the Fargo when completed.
Kona.jpg
fargo.jpg
by SIL4
19 Nov 2009, 8:50am
Forum: Bikes & Bits – Technical section
Topic: Drop bar v Alfine shifter compatability?
Replies: 4
Views: 526

Re: Drop bar v Alfine shifter compatability?

Plenty of info there - thanks very much.