Ask Fatdoc - the MTB technical thread (Read 81546 times)

SA Chris · March 23, 2009, 02:53:09 pm

So my old spds finally bit the dust (ripped off half of one on a rock), so switched to the new ones i got with bike. I have them set as loose as possible, but sometimes when I try to release my foot from them (by swinging heel out and down as I have always done) the toe hangs up and needs an extra wiggle to free it (with disasterous consequences once already). Any suggestions? Should you replace cleats on shoes when you get new pedals (my cleats are a bit rusty but no major damage). I have no idea what model of SPDs I have now and had before. Can take pics if required.

(and going for flat pedals is not an option, I have never had problems with spds until now).

tlr · March 23, 2009, 02:58:57 pm

Worn cleats don't release easily or fully, so that is one possibility.

Another, depending how old your pedals/cleats were is that there were 2 models of cleat (SH51 and SH52 I think) and they don't work quite right with the other model of pedal.

Either way, changing the cleats should fix it.

Yossarian · March 24, 2009, 12:38:28 pm

I had a very enjoyable ride around Bedgebury last night, despite my front Mono M4 calliper venting most of the hydraulic fluid from the front brake just before I set off, and hence leaving me with only my back brake to slow me down.

The leak was from the 90 degree connector, where the hose enters the calliper. The bolt had worked loose (I didn't realise this) and when I pulled the brake on the fluid squirted out all over the place.

I think it's probably down to the fact that I had the connector angle set wrong, so suspension action was pulling the connector back and forth and after a while this had caused the bolt to work loose.

Anyone else had this problem? I've never had an fluid leak from Hopes before.

On the other hand, the newly fitted Fox 36s are awesome...

Norton Sharley · March 24, 2009, 01:09:21 pm

Sounds like you need to use the hose guide, or better still a tie wrap, to stop your hose moving and undoing the banjo bolt.

Yossarian · March 24, 2009, 01:50:10 pm

i've got the hose guide attached. i will see if i can fiddle with it to improve the angle.

thing is, i had upside down forks before (maverick duc32) which are s'posed to be much more troublesome re front discs, yet they were absolutely fine.

when you say tie wrap, i assume you mean a vertical zip tied hose guide of some sort...?

fatdoc · March 24, 2009, 02:19:46 pm

Zip tie the hose to the frame some 5 to 10cm from the caliper.. to stop the tooing and froing of the hose working itself free from the bolt on the caliper..

Norton Sharley · March 24, 2009, 03:25:27 pm

You see, this is why he is a technical guru - apparently it's not a tie wrap but a zip tie.

See image and zip tie at top of fork lower. Make sure it's tight. If you don't snip off the excess then you can turn it into the spokes and get that wizzing sound we used to have as kids using cardboard and clothes pegs.

[another gratuitous bike shot]

[/another gratuitous bike shot]

SA Chris · March 24, 2009, 03:27:45 pm

Quote from: Norton Sharley on March 24, 2009, 03:25:27 pm

You see, this is why he is a technical guru - apparently it's not a tie wrap but a zip tie.

Tie wraps being the things used on freezer bags

Very pretty, very clean?

Norton Sharley · March 24, 2009, 05:16:34 pm

So are you saying that now it is summer I need to swap my tie wraps for zip ties?

fatdoc · March 24, 2009, 05:32:38 pm

Get those tasstles on yr bar ends back on whilst yr there mate

Pink, naturally.

Norton Sharley · March 24, 2009, 05:51:03 pm

I always find the problem is getting on lock on's with tassles, it's ok to get the old push on types. There's a gap in the market there

Oli · April 20, 2009, 12:32:19 pm

For all the DH/freeeride orientated members, any chainguide recommendations?
I'm looking to run a single ring and am not too bothered about having a bash ring at the moment. I've heard that some E13 devices have compatability issues with Saints and you need angle grind the inner ring tabs off, which'd be a bit of a pain. It's for ISCG old mounts btw.

fatdoc · April 20, 2009, 09:54:26 pm

PM fbsf, he dremeled a E13 onto my wolf ridge no probs, sdh forum is also good for this level of detail

Oli · April 20, 2009, 10:24:37 pm

Cheers. What have you got? a SRS guide?

fatboySlimfast · April 21, 2009, 08:45:19 am

I run a e-13 srs on my intense with diabolous cranks but have run a srs with saints no problem. get the correct back plate and you should be ok. Chain guides are a bit of a pain in the ass as there is no real hard and fast rules about fitting. It took me 5 attempts to get my srs on to my intense, thats 5 times taking the cranks on and off!!! The only important thing is keeping your chain line as much as possible.

Oli · April 23, 2009, 06:59:07 pm

Successfully managed to attach a E13 LS1 today, although I need to give it a test to determine how much rubbing/crap chainline there'll be. Hopefully not much.
Fitting wasn't helped by the fact that whoever built the frame seems to have managed to weld on the ISCG tabs a bit squiffy (or they're a bit bent) . Then had to take an angle grinder to the Saints because of the wack number of spacers I had to use.
Should work though, we'll see on Sunday.

Bubba · April 23, 2009, 07:00:44 pm

I had to tussle a bit to get my E13 DRS to fit the Big Hit - I'm not sure just how standard ISCG tabs really are.

fatdoc · April 23, 2009, 08:10:31 pm

IIRC there have been 2 ISCG tab types in the past and now there is another, which was devised by dave Weagle ( DW link suspension guru) that is now adopted by the industry global wide...

I agre though, the whole cahin guide thing is a dark dark art..

Oli · April 23, 2009, 09:05:33 pm

The new one's supposed to be ISCG05 isn't it? Which is supposed to be standardised...
Went out and everything seemed to be running alright, until the powerlink fell out as I didn't connect it properly and then I couldn't find it. Arse.

Yossarian · April 28, 2009, 06:29:59 pm

re my rear shock on the kona...

the spring says 600 x 2.5

is the 2.5 the shock stroke in inches? or something else? cos i can't find any writing on the shock itself.

and is the 07 stinky single pivot or something more complicated? i read something about faux bar, which is clearly something different to four bar!

yours

elephant man

Yossarian · April 28, 2009, 06:42:02 pm

i've just figured out that the stroke is 2.75"

which means i want a 400lb spring max.

so 600lb is a bit much, eh...

Oli · April 28, 2009, 06:58:33 pm

The 'faux bar' title refers to the fact that it doesn't have a Horst link and cannot be called a true four bar system (for some reason, presumably all down to patenting). So the rear wheel is in effect attached to the chain stay on your bike (I believe) while a Horst link effectively has the rear wheel attached to the seat stay as on fbsf's M3.

Edit: Looking at the tftuned site, if you're 85Kg in riding kit with a 2.75in stroke shock, a 450lb spring seems nearer the mark.

Yossarian · April 28, 2009, 07:32:43 pm

it would be, but that stinky has 7" of travel, not 8"...

Oli · April 28, 2009, 08:02:10 pm

Ah... That's good deduction your part to work out what I'd done!

Yossarian · April 28, 2009, 08:30:27 pm

I am a dedicated critical rationalist...

Your theory was sound. You were merely working with erroneous data.