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Search: Posts Made By: Mark Kelly
Showing results 1 to 50 of 644
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Forum: General Cycling Discussion
10-02-16, 12:48 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

If you're quoting WWII British planes, the...

If you're quoting WWII British planes, the obvious comparison is the deHavilland Mosquito. Faster than a Spitfire*, famously damage tolerant, made of wood.

de Havilland Mosquito.


* If both...
Forum: General Cycling Discussion
10-02-16, 12:35 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

https://c8.staticflickr.com/9/8519/29320873351_d86...

https://c8.staticflickr.com/9/8519/29320873351_d865cc93cf_b.jpg (https://flic.kr/p/LEZ98a)Bugger. (https://flic.kr/p/LEZ98a)

That is my fatigue tester per ISO4210_6...
Forum: General Cycling Discussion
09-20-16, 07:32 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

Yes, I am very bad at the website stuff, my...

Yes, I am very bad at the website stuff, my eldest son has taken over. Hopefully we'll be up soon.

One of the few things on the website that works is the top banner, which now says "Tonewood...
Forum: General Cycling Discussion
09-20-16, 07:24 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

If you are talking about my bikes, the key...

If you are talking about my bikes, the key difference is that the wood layers are built up in 0.6mm increments and impregnated with a high Tg epoxy ( Tg correlates with crosslinking) which is oven...
Forum: General Cycling Discussion
09-20-16, 07:09 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

I only work with Australian tonewoods from...

I only work with Australian tonewoods from sources I can trust.

Tasmanian blackwood (the wood on the medial faces of the tubes in the bike in the OP) is a close relative of Hawaiian koa if that's...
Forum: General Cycling Discussion
09-20-16, 07:05 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

I don't like them either, that's the last bike...

I don't like them either, that's the last bike that was or will be done with those joins.

The problem has always been that the tube joints are compound curves and wood won't bend over the compound...
Forum: General Cycling Discussion
09-20-16, 06:59 AM
Replies: 71
Views: 5,940
Posted By Mark Kelly

Hi, I'm the guy who makes these. Just to...

Hi, I'm the guy who makes these.

Just to clear something up, they are not carbon frames with wood veneer.

The build method is something I developed over several years of research, it involves...
Forum: Bicycle Mechanics
09-16-15, 07:05 AM
Replies: 22
Views: 1,605
Posted By Mark Kelly

The Centaur triple is the same size as the old...

The Centaur triple is the same size as the old AC-H double, 111mm, so the Campagnolo part you linked is exactly the same as the one I did (Campagnolo part number is BB5-CEH1I I think). Sorry if that...
Forum: Bicycle Mechanics
09-16-15, 06:18 AM
Replies: 22
Views: 1,605
Posted By Mark Kelly

The BB you have in now is an older AC-H or the...

The BB you have in now is an older AC-H or the cheaper SC-S (the only diff is that -H is a hollow axle), you can tell by the six "dimples" in the NDS cup. These are sealed bearing units, as are the...
Forum: Bicycle Mechanics
09-14-15, 05:42 AM
Replies: 22
Views: 1,605
Posted By Mark Kelly

Dual pivot Mirage brakes = '98 or later. The...

Dual pivot Mirage brakes = '98 or later. The weird downtube shape also says '98 or '99 (and the cable routing sugggests it was a cyclocross bike).

'98 Mirage was 8 speed, '99 was 9 speed, yours...
Forum: Framebuilders
09-08-15, 07:42 PM
Replies: 4
Views: 1,056
Posted By Mark Kelly

Made by Pelizzoli, see half way down this page...

Made by Pelizzoli, see half way down this page (http://www.pelizzoliworld.com/history/).

I'd replace the aluminium fork with steel or carbon, the dimensional constraints of forks mean that...
Forum: Framebuilders
08-24-15, 06:36 PM
Replies: 15
Views: 6,163
Posted By Mark Kelly

Doug: typo alert, you meant carbon dioxide (CO2)....

Doug: typo alert, you meant carbon dioxide (CO2).

There isn't enough CO in your air supply to need removing, while CO2 is currently 0.4% (and rising). If there was any CO a PSA wouldn't remove it...
Forum: Framebuilders
08-12-15, 08:59 PM
Replies: 32
Views: 4,029
Posted By Mark Kelly

If I read this correctly, he's got those and...

If I read this correctly, he's got those and wants the BB into which they fit.

Only fix I can think of is some 50.8 OD x 2.4mm WT 4130 tube and a couple of these taps...
Forum: Framebuilders
08-11-15, 09:02 PM
Replies: 32
Views: 4,029
Posted By Mark Kelly

470690 If you are not familiar with...

470690

If you are not familiar with eccentric contractions, think about running down a very steep hill: your quads are trying to contract while they are being extended.

The physically hardest...
Forum: Framebuilders
08-11-15, 07:03 PM
Replies: 32
Views: 4,029
Posted By Mark Kelly

OK, so the motor is providing 80% of the 900...

OK, so the motor is providing 80% of the 900 watts, now it makes sense.
Forum: Framebuilders
08-11-15, 06:09 PM
Replies: 32
Views: 4,029
Posted By Mark Kelly

"page not found"

"page not found"
Forum: Framebuilders
08-11-15, 05:58 PM
Replies: 32
Views: 4,029
Posted By Mark Kelly

I'd like to see some evidence for that. It...

I'd like to see some evidence for that.

It is extremely unlikely that anyone can produce 900 watts for 20 minutes: it would require 10 watts per kg from a 90 kg individual. Even for elite XC...
Forum: Framebuilders
08-10-15, 04:23 AM
Replies: 14
Views: 7,957
Posted By Mark Kelly

See reccent Cycling Tips "Bikes of the Bunch"...

See reccent Cycling Tips "Bikes of the Bunch" (http://cyclingtips.com.au/2015/08/bikes-of-the-bunch-cinelli-xcr/): 6.6 kg as built
Forum: Framebuilders
07-14-15, 05:35 PM
Replies: 8
Views: 3,568
Posted By Mark Kelly

Be careful with these unidirectional tubes: the...

Be careful with these unidirectional tubes: the cheapest ones are pulltruded and thus have all fibres along the axis of the tube, making them useless for framebuilding as the fibre orientation...
Forum: Framebuilders
06-17-15, 05:14 PM
Replies: 34
Views: 6,182
Posted By Mark Kelly

I agree with Vatdim. Curvy tubes are the output...

I agree with Vatdim. Curvy tubes are the output of designers, not engineers.

As the large companies push the envelope with frame weight, the curvy tubes are disappearing. Why?

Because a...
Forum: Framebuilders
06-06-15, 04:55 AM
Replies: 19
Views: 2,937
Posted By Mark Kelly

When using wet layup it's still worth having an...

When using wet layup it's still worth having an oven for curing or post curing at elevated temperature, it improves the Tg (shorthand for degree of crosslinking in the epoxy).

I make my own tubes...
Forum: Framebuilders
06-04-15, 06:32 AM
Replies: 19
Views: 2,937
Posted By Mark Kelly

Looks like you've bonded directly to the BB shell...

Looks like you've bonded directly to the BB shell on your frame (assuming yours is the larger one). Is the shell Al, Ti or steel? What surface prep did you use?
Forum: Bicycle Mechanics
06-02-15, 05:45 PM
Replies: 21
Views: 7,456
Posted By Mark Kelly

Campagnolo Veloce 10 speed...

Campagnolo Veloce 10 speed (http://www.chainreactioncycles.com/au/en/campagnolo-veloce-flatbar-shifters-10sp/rp-prod59851) flat bar shifters are available.

Probably easier to replace chain and...
Forum: Bicycle Mechanics
05-11-15, 05:42 PM
Replies: 21
Views: 1,224
Posted By Mark Kelly

I don't know what that means.

I don't know what that means.
Forum: Bicycle Mechanics
05-11-15, 05:26 PM
Replies: 51
Views: 5,591
Posted By Mark Kelly

I did, but I'll do it again for your sake, with...

I did, but I'll do it again for your sake, with supplementary notes:

5.26 is Rohloff's stated gear range, the thirteenth root is a necessary consequence of having 14 gears.

5.26 1/13 = 1.136...
Forum: Bicycle Mechanics
05-10-15, 07:24 PM
Replies: 51
Views: 5,591
Posted By Mark Kelly

13th root of 5.26. FB is right, I was just...

13th root of 5.26.

FB is right, I was just pointing out that your arithmetic was wrong.
Forum: Bicycle Mechanics
05-09-15, 04:51 PM
Replies: 51
Views: 5,591
Posted By Mark Kelly

That's not how maths works: it's 88.0% (1/1.136).

That's not how maths works: it's 88.0% (1/1.136).
Forum: Bicycle Mechanics
05-02-15, 04:26 AM
Replies: 27
Views: 5,240
Posted By Mark Kelly

Not a particularly good choice: although in most...

Not a particularly good choice: although in most circumstances common alkalis don't hurt Ti much, they are corrosive in the right (or wrong) circumstances: mix some peroxide into your sodium...
Forum: Bicycle Mechanics
04-27-15, 05:50 PM
Replies: 38
Views: 7,378
Posted By Mark Kelly

Yeah, misplaced attempt at humour, trying to play...

Yeah, misplaced attempt at humour, trying to play off it not making sense.

I should stick to what I'm good at.
Forum: Bicycle Mechanics
04-27-15, 05:29 PM
Replies: 17
Views: 3,827
Posted By Mark Kelly

447706 Elite Ciussi Gel in yellow. I have...

447706

Elite Ciussi Gel in yellow. I have two spare in my shed, shame you're not in Oz.
Forum: Bicycle Mechanics
04-27-15, 02:34 AM
Replies: 38
Views: 7,378
Posted By Mark Kelly

It's French.

It's French.
Forum: Bicycle Mechanics
04-26-15, 06:42 PM
Replies: 38
Views: 7,378
Posted By Mark Kelly

It probably means that the BB threads are not in...

It probably means that the BB threads are not in perfect alignment and / or the BB faces are not perfectly square. Roller bearings are far less tolerant of misalignment than ball bearings.

The...
Forum: Framebuilders
04-23-15, 08:42 PM
Replies: 3
Views: 984
Posted By Mark Kelly

Good luck with that: all the available Aluminium...

Good luck with that: all the available Aluminium BBs are intended for welding, not bonding.

For my first prototype I got around this problem by brazing a short length of tube into the lug socket...
Forum: Framebuilders
04-21-15, 04:26 PM
Replies: 13
Views: 4,781
Posted By Mark Kelly

In contrast to the previous replies, I've...

In contrast to the previous replies, I've actually done some of this: my last frame used epoxy bonded stainless steel chainstays.

446497 446498

I wouldn't bother with the screws, just use the...
Forum: Bicycle Mechanics
04-18-15, 09:12 PM
Replies: 45
Views: 11,525
Posted By Mark Kelly

The part that is often missed is that since...

The part that is often missed is that since maximal spoke tension is proportional to cross sectional area which corresponds to mass per unit length, you can replace the mass per unit length in the...
Forum: Bicycle Mechanics
04-15-15, 09:38 PM
Replies: 27
Views: 5,240
Posted By Mark Kelly

You're welcome. As Clifford notes, that mnemonic...

You're welcome. As Clifford notes, that mnemonic is for British standard (so maybe it should be BBBB).

BTW if memory serves the cups on that BB are aluminium, in which case the advice regarding...
Forum: Bicycle Mechanics
04-15-15, 08:51 PM
Replies: 27
Views: 5,240
Posted By Mark Kelly

Mnemonic: BBB = Bottom Bracket is Backwards, eg...

Mnemonic: BBB = Bottom Bracket is Backwards, eg Right hand side is Left hand thread, Left hand side is Right hand thread.

Drive side loosens going clockwise with the frame in front of you.

BTW...
Forum: Framebuilders
03-26-15, 07:28 AM
Replies: 29
Views: 6,084
Posted By Mark Kelly

It would be a good idea to take that message down...

It would be a good idea to take that message down or disguise the email somehow, spambots are everywhere.
Forum: Framebuilders
03-26-15, 06:56 AM
Replies: 29
Views: 6,084
Posted By Mark Kelly

You have mail. I'm also interested in the...

You have mail.

I'm also interested in the FD hangers in the last pic: do you know what diameter tubing the inside curve fits?
Forum: Framebuilders
03-26-15, 01:24 AM
Replies: 29
Views: 6,084
Posted By Mark Kelly

441268 How many sets of these dropouts do...

441268

How many sets of these dropouts do you have?

How much do you want per set?
Forum: Bicycle Mechanics
03-18-15, 04:32 AM
Replies: 29
Views: 18,217
Posted By Mark Kelly

Actually thinking about it for a minute, I...

Actually thinking about it for a minute, I realised I was wrong: the ratio will be

Cable pull 1 / Cable pull 2 = (diameter of pulley 1 + diameter of wire) / (diameter of pulley 2 + diameter of...
Forum: Bicycle Mechanics
03-18-15, 01:30 AM
Replies: 29
Views: 18,217
Posted By Mark Kelly

There's really no need, the ratio of diameters...

There's really no need, the ratio of diameters will be equal to the ratio of cable pulls, which is already established: Rear Shifting | CTC...
Forum: Framebuilders
03-10-15, 03:39 AM
Replies: 13
Views: 1,964
Posted By Mark Kelly

I believe <strike>Rob English</strike> won that...

I believe <strike>Rob English</strike> won that prize.

Edit: The prize was won by Sarto, Italy.

It coulda been a contendah...
Forum: Framebuilders
03-02-15, 01:35 AM
Replies: 14
Views: 2,139
Posted By Mark Kelly

That's not strictly correct, most adhesives will...

That's not strictly correct, most adhesives will have an optimal bondline thickness called out on the data sheet.

For the one I use, it's 0.1mm. Thicker bondlines are weaker because of the lack of...
Forum: Bicycle Mechanics
01-15-15, 06:09 PM
Replies: 160
Views: 22,569
Posted By Mark Kelly

It's 2015 already: is that a Mr Fusion above the...

It's 2015 already: is that a Mr Fusion above the fork, and is that how you are powering this?
Forum: Framebuilders
12-14-14, 06:49 PM
Replies: 31
Views: 5,318
Posted By Mark Kelly

The motorcycle people sometimes talk about the...

The motorcycle people sometimes talk about the ratio of front normal trail to rear normal trail; normal here is in the geometric sense ie at right angles to the steering axis. Explanation...
Forum: Bicycle Mechanics
09-14-14, 06:07 AM
Replies: 13
Views: 1,442
Posted By Mark Kelly

Well you have disposed of the solvent, you've...

Well you have disposed of the solvent, you've just done it by emission to atmosphere. Not the most environmentally friendly way of do so.

I would imagine, however, that in NYC you are a net...
Forum: Bicycle Mechanics
09-14-14, 06:04 AM
Replies: 25
Views: 4,586
Posted By Mark Kelly

You'd basically end up with hydraulic seals,...

You'd basically end up with hydraulic seals, which are designed to prevent leakage of low viscosity oils.

Might as well not both having the bearings, there'd be little difference in friction.
Forum: Bicycle Mechanics
09-12-14, 11:30 PM
Replies: 33
Views: 2,260
Posted By Mark Kelly

A few years ago when ceramics became fashionable...

A few years ago when ceramics became fashionable I measured some jockey wheel pulley bearings directly, comparing plain bushings (Campagnolo original) to steel and ceramic ball bearings.

IIRC...
Forum: Framebuilders
09-12-14, 11:20 PM
Replies: 3
Views: 1,158
Posted By Mark Kelly

Did I nap too long and it's April already?

Did I nap too long and it's April already?
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