Current Projects chat and miscellany

I'm just short.

Malaysian - yeah it's surprising how cheap you can find things on ebay at 4am (insomnia has it's perks).
I'd rather not have a tensioner or any other bumf that could get bent if i'm dirt jumping. magic gear me thinks. ha, cheers about the stitching.
Nice GT by the way, nothing wrong with V brakes.

Cheers, had the GT since I was 11, it's just slowly evolved! Those v brakes are actually more powerful than alot of disc brakes I've tried, however as soon as they get wet/muddy braking is less effective and they can rub.

Building a singlespeed MTB for my sister, gonna be a simple city bike. really don't want to use a chaintensioner, as I've had a couple of friends who've experienced problems running them. My sister is about as mechanically minded as a Daim bar, so the bike just needs to be set up once and never go wrong.

when you finish this I'd be interested to know how easy it was finding a magic gear, and if you have any problem with chain slack once it stretches a bit.

I don't think chain tensioner are a problem, had two of them before and they're effortless.

and because it's going to be for your sister, whom intend to use it as an simple city bike, I'm sure it'll more than enough.

I'd be interested to know how easy it was finding a magic gear

These two links are useful
http://eehouse.org/fixin/formfmu.php
http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html
As long as you get it right to start with use single-speed specific rings, sprockets and chain you're chain will be worn out before the amount of slack becomes an issue.

Building a singlespeed MTB for my sister, gonna be a simple city bike. really don't want to use a chaintensioner, as I've had a couple of friends who've experienced problems running them. My sister is about as mechanically minded as a Daim bar, so the bike just needs to be set up once and never go wrong.

when you finish this I'd be interested to know how easy it was finding a magic gear, and if you have any problem with chain slack once it stretches a bit.

'mechanically minded as a Daim bar', chortle chortle.
Sure i'll post it up when it's finished, the idea of a stretching chain, halflinks and calculating tension is scaring me :/

mdcc cheers for the links like

the idea of a stretching chain

is a figment of the imagination. Chains don't stretch, they get longer when under tension due to increased clearance between the pins and the inner plates.

*coughs

is a figment of the imagination. Chains don't stretch, they get longer when under tension due to increased clearance between the pins and the inner plates.

people keep saying this, but I dont think many have actually tested/measured for it themselves.

Which is odd, since the proof is trivial. Take a worn chain, lay a sample length flat on a surface and pull the free ends apart. It will be longer than a new chain. Now push the free ends together, keeping the chain straight. It will be the same length as a new chain, or fractionally shorter. The difference is the free play in the bearings, and the fact that it can be pushed back to its original length shows that the plates themselves have not got any longer.

As long as you get it right to start with use single-speed specific rings, sprockets and chain.

I understand need for a strong chain, but would using a 3/32 standard chainring be a problem?

the idea of a stretching chain, halflinks and calculating tension is scaring me :/

^^^ this

The difference is the free play in the bearings.

this is "chain stretch" then ?

I understand need for a strong chain, but would using a 3/32 standard chainring be a problem?

Normal dérailleur chain is plenty strong enough, but the cutaway/chamfered side plates and bushingless construction are designed to make the chain come off the rings and sprockets as easily as possible. Ditto for rings and sprockets designed for use with dérailleurs, they have lowered and chamfered teeth to derail the chain. Wippermann make good cheap singlespeed specific chain in 3/32 and 1/8, and singlespeed specific sprockets and chainrings with a full complement of tall teeth are available from cheap to very expensive.

this is "chain stretch" then ?

No, it's the chain getting longer as it wears. It's also nit-picking pedantry, since the effect is the same, but the material doesn't get elongated, some other material gets worn away and the structure gets elongated.

Ah right I knew about the ramps and cutaways, never realised the teeth were shallower though.

Your explanations do make me chuckle sometimes, very informed. I understand you say the material doesn't stretch, what I meant with the " " is this is what people refer to as chain stretch.

It's also nit-picking pedantry

This.

Although, I have always bit my lip when someone has said the words chain stretch.

+1, markings and shape look right.

Cheers guys!

been through this a few times. A definition of stretch is "To lengthen, widen, or distend"
Yes it lengthens because of free play in the bearings but it lengthens so therefore stretches.

Anyway, the only time I tried it it went from a good tightness to a point where the chain would come off when going over bumpy ground in a matter of a month (using new chain to start)
That was enough to put me off (especially as the chain came off when going down a hill at 30mph)

*coughs

Dr:
Well, everything seems in order Mr Tull, your next check up will be in two years. Good day.

*scurries out "cheers Doc"

Dr:
Oh and I would suggest pulling your trousers back up before you leave!

(some of our older patients may be offended)

oops, sorry

*blushes

It's pretty...

Though that bike specifically isn't a current project. A current project is to research and build a good value 29er. One that is perfectly capable of doing long distance road trips (with a bunch of track bikes as company) as it is of blasting around the tow paths and having some fun on some dirtier tracks in Richmond Park and beyond... and perhaps some CX this season.

I really like the look of the Niner S.I.R. (Steel Is Real) 9 frame, which uses Reynolds 853 and is pretty sexy sans-braze-ons for things I wouldn't use. I also love love love the look of the Niner AIR 9 Carbon but that's a bit beyond my price range.

Also like the look of the Surly Karate Monkey if I find the Niner is too expensive. The only problem with the Surly is that whilst it's more adaptable I find the look of the brake mounts and stuff to be a bit fugly. Yet it's a rock solid frame.

Need to do more research, but it look like a tough 29er is in my future.

One that is perfectly capable of doing long distance road trips (with a bunch of track bikes as company) and perhaps some CX this season.Yet it's a rock solid frame.

You're right its a beautiful bike but....
Surely something like a fixed or SS Cross Check or Kaffenback would be better suited? Maybe built up with flat bars and HS33s?

The Robin Mather I have covers the kind of ground that the Cross Check and Kaffenback cover. I've dinged the paint enough to not feel so precious about it. I'm looking for something a little more reckless and fun, more throw around and playful but that isn't a trials bike (which I could never do justice), and that could put in the miles so that I don't end up with a limited radius (sometimes doing a day blasting along a canal or river tow path is all I want to do, and I don't want to sacrifice speed doing it).

The "keeping up with the track bikes" thing is more for things like the bridges rides. If I wanted to bring along the fun bike, I wouldn't want to be left for dust on the sprints between the bridges.

So... fun with speed. Throw around and playful riding.

You're right its a beautiful bike but....
Surely something like a fixed or SS Cross Check or Kaffenback would be better suited? Maybe built up with flat bars and HS33s?

I would second that. Don't see the point of using a 29er as the advantage that gives over a cross bike is that you could use some very knobbly 2.3 tyres. The last thing you need if keeping up with track bikes on the road and also not required for tow paths or cyclocross.

The limiting factor whether you use a 29er or a cross bike is the gearing choice. If you want to stick to one gear then you need to gear down for off road which makes it tougher to go as fast on road.
I use a 61GI which is perfect for the fast off road, 17mph average, that I ride (but is a struggle on technical uphills).
As soon as I am on a road section I simply cannot keep up with roadies as 20mph+ becomes a bit of a chore at 61GI and I can't go any higher without cocking up off road ability.

I have made a big assumption that this is going to be an SS bike off course.

I use a 61GI which is perfect for the fast off road, 17mph average, that I ride (but is a struggle on technical uphills).
As soon as I am on a road section I simply cannot keep up with roadies as 20mph+ becomes a bit of a chore at 61GI and I can't go any higher without cocking up off road ability.

I hadn't even thought of that, I was once told that the best ratio for proper* off roading is 2:1 so I run 32:16 on my SS Inbred but I find I can spin out on fast single track and to be honest I've not tried climbing on that gear, I live in Cambridge...

*Trail centers and man made trails, i.e. not towpaths and bridalways