So, I have an old Holdsworth that is currently doing fixed duties.

Ratio is a pretty standard 44×16.

If I was to try to convert it to a SS cross bike (just for a laugh, like), can you tell me:

1. What the normal SS cross ratio is – do we still follow the MTB principle of 2:1.

2. I asume that, if I wanted to follow the 2:1 principle, and run say 42×18 or 40×20, then chain length wouldn’t change from what it is currently, right?

3. Freewheel recommendations? Won’t be main use bike, so massive longevity not needed.

4. I’m using the old Weinmann centre pull brakes. Any idea what tyre width will go though here and still work well off road?

Cheers for any and all answers..!

OMITN

1. i used 39×18
2. yep pretty much, difference is only slight.
3. white industries, end of.
4. no idea but 30c is enough for most things.

Cheers STATO – mush appreciated!

1. 2:1 only if you’re a beginner. Go much bigger unless you’re racing or climbing massive hills.
2. 18 is not half of 42 😉 But yes, the difference wouldn’t be huge.
3. Yep, white indutries. Use Shimano or ACS at your own risk.
4. No idea.

I used to run 27×1 1/2″ tyres with my Weinmann centre pulls back in the Jurassic era. That’s about 38mm.

Samuri – no racing.

I was just trying to maintain the same chain length, given there isn’t much room for manoeuvre in the dropouts.

What would you recommend for flat stuff?

White industries is a bit more than I was hoping to pay for occaisional use..!

epicyclo – perfect – that means 32c or 35c will be fine. Of course, the brakes are hopeless, so it’s academic anyway..!

my shimano freewheel has been good to me; done about 2 years. just keep an eye out for funny noises or slipped engagement and ditch it as soon as you notice.

I’m running 34:18 on my Solitude, with 1.6″ (42c?) tyres. It’s almost a sscx bike.

That’s too low for flat stuff, though I can happily spin away at 20kmph forever. Debating whether to go for a higher gear, but I’ve some reasonably steep and long climbs round here.

I think I still need to go higher.

No idea what freewheel I’m running but it’s done me for 3 years of my usual neglect, including some winter commuting. It was cheap in Halfords.

20kmph

Woah! Moon launch speeds, maaaaaan 🙂

I get nosebleeds if I go any faster 🙂

Might rename you Ham.

oh yeah; 42:18 and i can climb most stuff.

I do have a 20T freewheel for a bigger day out (SDW) but we’ve never done it and the freewheel remains unused.

I’d say about 42:16 for the flat. You can move along quite fast in the spin on that.

What reasonably-priced 42t chainring? (5-arm, 110bcd)

Hmm. Been to see Sheldon. 42×16 is 69″ (I’m currently riding 72″, fixed). 44×18 would be 64″, which may work a bit better for my route (and may mean I can remain fixed – for a laugh).

Ideally, I don’t want to change the chainset (it’s a single, permanently attached ring – Stonglight ST55), so playing with the sprocket size is easier.

Mike – no idea, sorry…!

Surly chainrings are reasonably priced considering how long they last.

42:19 or 59.6″ here gets me up most South Pennines stuff and it’ll stay that way for next Sunday in Yorkshire.

White Ind all the way for something durable and used hard or ACS for occasional use.

cheers.

mocha – good luck in the 3PX..!

I’ll track down a couple of freewheels to give the lower ratios a crack. It’ll make my commute more interesting if I can jaunt alongside the Mersey on the way to Irlam.

Just found Goldtec DH chainrings for £15 – http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=33&Name=Goldtec+Chainrings

Amusingly enough, i’ve just built myself a very similar project. I’ll list the spec rather than a photo as it is back in bits at the mo -i’m going to respray it, but the spec is:

old ? lugged frame, horizontal forward facing drop outs with Weinmann centre pull brakes.
I’m running my old ultegra wheels with 32x 700c tyres on it: a fast fred cx on the front and Conti travel contact touring on the back. (these may change!) Brakes would take much more, but the frame is rapidly losing mud clearance space, so 32mm it is.
Old deore square taper cranks with 32t ring. rear is running 15t, so a bit higher than a usual ss gear.
The bars are on-one midge bars, which are proving to be ideal for this.

The ride is ok, not the lightest, but a bit of give over roots and rocks, the ratio is fine for me off road, but on flat road it is a bit low for my usual spinning pace. I’m hoping to reduce the rear sprocket when i’m a bit more played in with the single gear, as i haven’t ridden one for a while.
Might even run a flip flop hub, with a higher ratio fixed for the road sections, if i really get into it!

Mike – don’t order one..!

I’ve just remembered I have a Blackspire 5arm 110 bcd ring lying around. It’s 44t if you’re interested.

Have emailed you.

Tom

johnny – sounds almost exactly what I’m thinking of doing.

It’s good to know the brakes will take large enough tyres. I’ll have a look at frame clearance, but I suspect that 32c will be fine, and 35c will also be OK. Might have to play with the mudguards, though.

Hmm. Bars on mine are Cinelli road bars, so not altogether off-road friendly. However, if I raise the stem a bit they should do the job.

This could be a (cheap) laugh..!

Yes, cheap laugh is about right- ithing when mine is done it will have cost a little over £50, as most of it was lying around anyway!

If the cinelli bars don’t do it for you, i thoroughly reccomend the on-one midges- they are a lot more off road friendly, as well as being a lot wider for ss-ing.

WIll post photos when it’s done- be warned, it is freakish! 😉

Have you all seen http://www.63xc.com/ ?

Ihave, Mr McT, tho’ I’m not a regular reader. Will check out some of the info on there.

PS I’ll post that chainring on Weds.

and may mean I can remain fixed – for a laugh

Just remain fixed anyway, it solves your freewheel problem and it’s not like you have any issues with riding fixed.. I reckon it’s a non-problem anyway. My commute is mostly offroad and I ride that fixed. Your legs remember quickly enough and riding offroad fixed is much easier than riding down a big hill fixed on the road.

Oldgits tip of the day.

If you have an old 60/70s steel frame, a Mig welder and four canti bosses you can make your own crosser.
The old frames made for 27 x 11/4″ wheels will take 700c wheels with cross tyres easily.
The cheaper non 531 frames take Mig welding no problem. So fitting the bosses is a doddle.
They’ll also have ‘long’ drop outs so running it singlespeed is okay. 5/6 with bar end friction shifters otherwise.
Bottom bracket height, ignore that bit it’ll never be a problem.
Powder coat the whole lot.
Jubly.