Fixed/Single Speed Commuting

Clever Pun

Attica wrote:

QFT

Wha da?

Quoted For Truth

UnworthyPapaLazaru

for a cadance computer your looking 35-40 notes.

http://www.edinburghbicycle.com/ebwPNLq ... 132c003189

Littigator

Clever Pun wrote:

Attica wrote:

QFT

Wha da?

Quoted For Truth

Do you play role playing games and stuff?

Clever Pun

Littigator wrote:

Clever Pun wrote:

Attica wrote:

QFT

Wha da?

Quoted For Truth

Do you play role playing games and stuff?

no and frankly you might get a black eye for that sort of accusation :x

It's a reasonably well used interweb phrase

Littigator

If you weren't much bigger harder and scarrier than me I'd have you ina second! Come and 'ave a go if you fink yer 'ard enough

Aaarrgghhh....ducks and runs for cover

wgwarburton

LiT writes:

> What's the cheapest cycle computer with cadence on it? I'm curious. Could do the maths, but can't be @rsed.

Well, I got a Halfrauds £5.99 computer for the winter hack and calibrated it to read cadence instead of mph. This is the cheapest way to do it, but it does involve either doing the maths or getting someone to do it for you...

You can recalibrate for speed later, or buy another one- cheaper than a multifunction computer, but probably won't last as long...

There's a suggestion on how to do it on the 63xc website, but the writer puts the sensor on the cranks- if you are using a single fixed gear then you can leave the magnet on your wheel and just factor in another conversion factor, since the wheel and crank speed are inseperable...
Let me know if you want more detail.

Cheers,
W.

Jen J

Sorry, by SCR I did mean the racing thread. But having stopped being quite so lazy, I looked at it, and lo and behold, the very first post explains it all. :oops:

lost_in_thought

Hmmmm, sounds complicated Buns, maybe not for a man of your calibre!

I think I might look into upgrading my cateye...

itboffin

WGWarburton wrote:

LiT writes:

> What's the cheapest cycle computer with cadence on it? I'm curious. Could do the maths, but can't be @rsed.

Well, I got a Halfrauds £5.99 computer for the winter hack and calibrated it to read cadence instead of mph. This is the cheapest way to do it, but it does involve either doing the maths or getting someone to do it for you...

You can recalibrate for speed later, or buy another one- cheaper than a multifunction computer, but probably won't last as long...

There's a suggestion on how to do it on the 63xc website, but the writer puts the sensor on the cranks- if you are using a single fixed gear then you can leave the magnet on your wheel and just factor in another conversion factor, since the wheel and crank speed are inseperable...
Let me know if you want more detail.

Cheers,
W.

Yep more info would be good, I've been wondering for a while now what my avg. cad is i'm guessing very very slow.

itboffin

I found this interesting howto http://www.instructables.com/id/SMFS5VDFIDCX52F/ if you read the comments on the last page as well it makes the whole set-up much easier and as suggested you could just use Sheldon GI calc to workout your (MPH @ RPM) then you'll know when you're above or below personal limits.

By those calcs my SS 170mm cranks, gear ratios currently 46/16T (yes still waiting for my MASSIVE ring) my avg. commute speed 18 MPH therefore my avg. RPM is 80.

Mmmh I don't think so somehow....

wgwarburton

Biondino wrote:

> Yes, partly as a potential single speed convert...

OK. Had a look. That's a good candidate for a fixie- the frame's nice, not the lightest steel frame but an honest, quality build. I can't see what the geometry looks like very clearly, but going by the clearances I expect it's a classic long wheelbase "touring" frame- should handle nicely: stable and quite comfortable.
The main frame tubes and forks are Reynolds 531, good quality steel, if not the best double-butted stuff, nor the lightest, thin-walled version.
Dropouts are horizontal and proper forged ones, not cheapo pressed steel, by the looks of them. Chainset is OK- alloy, not steel and again, decent, not a cheapo one with the chainring pressed onto the crank, I think. I bet you could get some single-ring bolts and turn the big ring round , so that the chain runs on the opposite side of the teeth and hence get a lot of miles out of it, yet.
Bars & stem are alloy, brakes look useable (but you'll need to ditch the suicide levers- probably means replacement- I think Shimano still do a basic lever, or there's eBay), pedals look useable, can't tell if the seatpost is steel, but it'll likely be a standard 27.2mm one if you want to change it.
You could re-use the wheels, if the rear's a freewheel- get it off (LBS?), re-dish the wheel to correct the chainline and put on a sprocket, maybe with a BB lockring for peace of mind.
I expect you could do it for about 50 quid, or not much over. Or you could push the boat out, get a respray, new wheels etc and end up with a nice looking bike (those Lugs will come up nicely if you line them!). The 50 quid assumes a tenner for a sprocket, ten to fifteen for a chain and ring bolts, twenty quid for brake levers and re-using everything else, with a bit left over for bar-tape, hammerite(!) etc. If you need to farm out the wheel work, or replace anything else (BB? saddle? tyres?) that'll obviously push it up.

What would it cost to buy an OTP fixie of similar quality? Hard to say, but I would rate it as above entry level, for sure... It ought to weigh in at about 11Kg or less and ride better than a cheap aluminium frame, though that's a personal preference thing.

Definitely worth doing, especially given that the drivetrain looks shot already, so the alternative would be an expensively comprehensive repair or scrap :-(

Cheers,
W.

biondino

Thank you Buns (I hope you don't mind your nickname, I think it's great!) - that's incredibly useful. The bike was ridden last about 4 years ago by my ex (she's 6 foot so fitted the bike okay) and worked at the time, but has been in a shed ever since.

I'd certainly need to develop my bike skills if I were to try and do it myself, but I'd very much like to do that so this might be the perfect project to work on. I suspect I'd need to spend another £50 at least on tools as I really don't have everything at present, but that's okay.

Again, thank you - I really appreciate your time and expertise. I may have more questions if I do decide to take up the challenge!

Clever Pun

Had my first really feeling the road moment today

leaning coming round a corner and my back wheel touched a manhole cover and slid out a bit while my legs tried to accelerate... felt pretty weird but I straightened it up easy enough as I only caught the corner...phew

wgwarburton

itboffin writes:

> Yep more info would be good

OK, here we go:

The computer I used is a "Halfords 5 Function Bike Computer". Their website has it at £6.99, now. Maybe that's what I paid for it.
Some computers won't work because the calibration is set up for sensible sizes of wheels and sane speeds.
What we are doing is persuading the computer that we are travelling at up to 150mph on a bike with small wheels. We can fudge it a bit if the computer can't handle that, though.

There are several ways to skin this cat, but the principle is that the computer calculates speed by counting wheel revolutions. If you move the magnet that does the counting to the crank, you can count cadence instead, "correcting" the wheel size by changing the computers calibration number to get the correct readout. Martin King describes how to do that here:
http://www.63xc.com/martink/cadence.htm

We observe, however, that this is an unnecessary pain in the posterior, if you only have one gear, because the wheel speed and crank speed are directly linked (unless you freewheel, of course, but why would you want to do that?).

So, we find the normal calibration number for our wheel size. In my case, and for the Halfrauds 5f, this is 2136 (wheel circumference in millimetres for a 200x28c tyre, other tyre sizes and computers may have a different number). To get a reasonable estimate of a conversion note that Rabbit:

http://software.bareknucklebrigade.com/ ... pplet.html

Suggests that I will be turning 100rpm at 18.8mph. If we scale 2136 by this ratio we get

18.8
---- X 2136 = 402
100

Update the computer to have a wheel diameter of 402mm and when doing 18.8mph it will read 100rpm or, more plausibly, try scaling by 10 and use 4020. You then get a display of 10.o, which you can interpret easily enough.
If your computer is restrictive about the ranges it will accept, then choose a factor that allows for easy mental arithmetic- 804 in the example above would give a display of 50- which you can double for actual cadence.

This is an easy way to understand what we're doing, but I think the assumptions and nominal figures result in a pretty rough approximation. A more methodical approach is to take the calibration adjustment that Martin King uses for a crank-mounted sensor and scale by your gear ratio. In my case that starts with the computer's basic formula

( C x R x 60 )/ 1,000,000

Circumference of wheel (mm) x rpm x 60 divided by 1,000,000 to get kilometres per hour

Solve for C to get 1,000,000/(10X60)=1670

Then scale with the gear ratio to translate crank revs to wheel revs:

52
---- x 1670 = 3950
22

This is quite close to the 4020 figure I got above, but should be more accurate because we havn't added and then subtracted two estimates of my actual wheel diameter from different sources...

The wheel size is, in fact, irrelevant- we are measuring cadence by counting revolutions, either of crank or wheel. A bigger wheel will turn more slowly at a particular roadspeed, but then so will your legs, the cadence will still be correctly displayed.

Moving the sensor to the crank or fitting extra magnets to the wheels are less elegant ways to achieve the same result. This may involve a little more arithmetic but you don't have to extend wires or buy extra magnets, and you can change from rpm to mph and back by simply changing the calibration number (though you'll lose any information, like mileage accumulated, when you do so). If you have variable gears (how modern!) then crank mount is the way to go.

Cheers,
W.

Cantdosleepy

Does anyone have any knowledge of Charge bikes? My work has finally sorted out the cycle to work scheme, but we have to go through Evans.

I'm more-or-less certain that I want a single speed (I'm only going to be commuting in the flattest parts of London, never left the highest gear on my old mountain bike, been enjoying the battered old fixi I acquired recently) and Charge seem to be the range they carry. There's a review of the Plug on here - http://www.bikeradar.com/gear/category/bikes/road/product/plug-07-20542 - but I'm after a cheaper one, I reckon...

il_principe

Arghhhh this thread has gone all techy. What's all this maths business, I swear I saw the word "arithmetic" somewhere.

ENOUGH. This is a thread about purity, simplicity and the perfection that is 1 Gear.

No more complex mathy stuff please, it gives me a rash.

Oh and I'm getting rather worried by the number of people contracting spinnyitis.

MTFU people, MTFU.

lost_in_thought

lol...

I just tried to read buns's's's thread and I think my head exploded. :shock:

I'm just going to get a computer which measures cadence. I'll pay £35 to not have to understand that thread!

And my gear is staying exacty how it is.

Greg T

I took a quick look at the hypermathematics involved in working out the cadence from wheel speed then decided I'd be better off just buying the cadence monitor.......

I have a distant and somewhat random relationship with numbering and hard sums that's best not provoked......

I had an epic high rpm battle last night with a London Dynamo dude on a singlie. We were both spinning rapiiiiiddddooooooooo

He was surprised that i done him on the Embankment, surrrised I done him on Parsons Green and was gutted when I done him on Lower Richmond road when he was defo trying.

I'm working on the "weightless" pedalling thing and it's going well, when I'm slicker than a bucketful of eels I'll drop a tooth off the back and work it up again.

wgwarburton

Pah! This is what happens when they stop teaching science at school! :-)

You don't have to understand it, anyway- just plug in your numbers.

Using the Halfrauds 5f- set up as per the instructions and instead of entering your wheel size to read speed, enter:

1670*(46/14)=5490 (for LiT's 46/14)
or
1670*( 48/18 )=4450 (GregT's current 48/18 )

Easy- the work's done for you. You don't even need to faff around with longer wires or extra magnets.

A different computer may have a different adjustment (eg cm instead of mm or radius instead of circumference). Just ask.

Cheers,
W.

Greg T

WGWarburton wrote:

1670*(46/14)=5490 (for LiT's 46/14)
or
1670*( 48/18 )=4450 (GregT's current 48/18 )

Oh Cheers for that Buns!

Just so we are all clear on my shrivelled and prawn like man horn you have to post my and LiTs relative gearings one above the other.

Thanks a Bunch.

Clever Pun

jashburnham wrote:

Arghhhh this thread has gone all techy. What's all this maths business, I swear I saw the word "arithmetic" somewhere.

ENOUGH. This is a thread about purity, simplicity and the perfection that is 1 Gear.

No more complex mathy stuff please, it gives me a rash.

Oh and I'm getting rather worried by the number of people contracting spinnyitis.

MTFU people, MTFU.

yeah lets listen to the man with the 20 yard commute

wgwarburton

Greg T writes:

> you have to post my and LiTs relative gearings one above the other

Yeah, but only after posting my example of a 52x22 (63"), which is what I rode in on this morning.

It's chucking it down, here, and wild winds are forecast. Besides big sprockets are more efficient and reduce drivetrain wear (lower chain tension, donchano) ... I may be taking that too far, though...

Litt's reckons spinning looks silly. I reckon crutches look worse... :-)

LiT- did you check your crank length? I don't know what height you are but it could be that you would be more comfortable on shorter ones.

Cheers,
W.

lost_in_thought

WGWarburton wrote:

Greg T writes:

> you have to post my and LiTs relative gearings one above the other

Yeah, but only after posting my example of a 52x22 (63"), which is what I rode in on this morning.

It's chucking it down, here, and wild winds are forecast. Besides big sprockets are more efficient and reduce drivetrain wear (lower chain tension, donchano) ... I may be taking that too far, though...

Litt's reckons spinning looks silly. I reckon crutches look worse... :-)

LiT- did you check your crank length? I don't know what height you are but it could be that you would be more comfortable on shorter ones.

Cheers,
W.

I actually looked into the chain wear thing and decided on the back of my research that a half-link with a specific small-sprocket bmx design was needed. I actually had to splice 2 chains together, but it seems to run pretty well. It's about a link too long, but I can sort that out when I'm feeling less lazy!

As for the cranks, no, not yet, will have a look on my way to the gym. I'm 5'8".

camvaile

Cantdosleepy wrote:

Does anyone have any knowledge of Charge bikes? My work has finally sorted out the cycle to work scheme, but we have to go through Evans.

I'm more-or-less certain that I want a single speed (I'm only going to be commuting in the flattest parts of London, never left the highest gear on my old mountain bike, been enjoying the battered old fixi I acquired recently) and Charge seem to be the range they carry. There's a review of the Plug on here - http://www.bikeradar.com/gear/category/bikes/road/product/plug-07-20542 - but I'm after a cheaper one, I reckon...

Cantdosleepy. I have a Charge Plug (the shiny chrome racer). And I think it's great. I'm sure I'll be panned by many out there who turn their nose up at an off the peg SS (especially a chrome one at that). And I know it's not the lightest single speed out there, but compared the fat old mountain bike I was riding it's light and fast and the most fun I've had getting to work ever.

I did make a few changes once I got it. Upped the chainring from the stock 42T to a 48T (which required a new chain) straight away and have since changed the tyres so I could run higher pressures. Also changed the rubbish old style drop bars for bull horns. In the end these were personal prefences and the bike is pretty much how I want it now. Only thing I'm still toying with is a smaller back freewheel to up the gear a bit more, although I think they're fairly hard to find unlike sprockets.

Hope that helps. Evans do a fair few other SS too, but if you like the look of the Plug have a ride and see what you think. I'm sure one or two others on here might suggest a Bowery though....

wgwarburton

camvaile writes:

> Shiny Charge Plug Racer (Nitto Bullhorns instead of those ridiculous drop bars)

What's ridiculous about them?

Also:

> ...I know it's not the lightest single speed out there...

Seems to be quite hard to find really light OTP fixies without spending a lot of money. I guess so much of the weight is in the frame & wheels that the prices ramp up pretty steeply. If the main market is for low-maintenance commuter bikes then I guess that accounts for it.

Cheers,
W.

lost_in_thought

lost_in_thought wrote:

WGWarburton wrote:

Greg T writes:

> you have to post my and LiTs relative gearings one above the other

Yeah, but only after posting my example of a 52x22 (63"), which is what I rode in on this morning.

It's chucking it down, here, and wild winds are forecast. Besides big sprockets are more efficient and reduce drivetrain wear (lower chain tension, donchano) ... I may be taking that too far, though...

Litt's reckons spinning looks silly. I reckon crutches look worse... :-)

LiT- did you check your crank length? I don't know what height you are but it could be that you would be more comfortable on shorter ones.

Cheers,
W.

I actually looked into the chain wear thing and decided on the back of my research that a half-link with a specific small-sprocket bmx design was needed. I actually had to splice 2 chains together, but it seems to run pretty well. It's about a link too long, but I can sort that out when I'm feeling less lazy!

As for the cranks, no, not yet, will have a look on my way to the gym. I'm 5'8".

And my cranks are 170mm ones, which I guess is pretty short? Appropriate for someone who's 5'8"?

biondino

170mm is probably just right for you. Also, track bikes have shorter cranks than road bikes fwiw.

Clever Pun

camvaile wrote:

Also changed the rubbish old style drop bars for bull horns.

Boo Hiss

Cantdosleepy

camvaile wrote:

Cantdosleepy. I have a Charge Plug (the shiny chrome racer). And I think it's great. I'm sure I'll be panned by many out there who turn their nose up at an off the peg SS (especially a chrome one at that). And I know it's not the lightest single speed out there, but compared the fat old mountain bike I was riding it's light and fast and the most fun I've had getting to work ever.

I did make a few changes once I got it. Upped the chainring from the stock 42T to a 48T (which required a new chain) straight away and have since changed the tyres so I could run higher pressures. Also changed the rubbish old style drop bars for bull horns. In the end these were personal prefences and the bike is pretty much how I want it now. Only thing I'm still toying with is a smaller back freewheel to up the gear a bit more, although I think they're fairly hard to find unlike sprockets.

Hope that helps. Evans do a fair few other SS too, but if you like the look of the Plug have a ride and see what you think. I'm sure one or two others on here might suggest a Bowery though....

Thanks!

Went into Evans just now and had a sit on some of the bikes there - the Carge Plug was by far the comfiest. Filling in the forms now - can't wait!

wgwarburton

LiT Writes:

> And my cranks are 170mm ones, which I guess is pretty short? Appropriate for someone who's 5'8"?

I wouldn't say they were short. 170mm is "standard" and I was thinking that if you were small you might be more comfortable with shorter ones.

I'd say they're probably about right. If you look at the guidelines that itboffin posted earlier you'll see 170mm recommended for up to 5'10. Women generally have longer legs for the same height than men, anyway, but track/fixed riders will often go down a size. Given that you prefer to push a big gear they're probably spot on.

It occurred to me from an earlier posting of yours, where you said you found high cadences awkward that you might be 5'2" and using 177.5mm cranks. Clearly not the case! just down to personal style.

Cheers,
W.