H plus son TB 14 rims

[Gattonero]

I know a guy who claims he can distinguise a radial spoked front wheel from a similar one spoked with 2 cross.
Same nonsens.

The nonsense is to raise such point. Completely different things we're talking.
Try different rims, then talk. Thanks.

The point is not "one is better than another", the point is "can be different".

[Brucey]

I struggle with this whole argument because on the one hand I know what Colin says is true, yet wheels appear to feel different to me, too.

Thinking out loud here, what if the loads are much more than 50kg? What does 'the system' actually look like that passes road bumps into the handlebars?

On the first point suppose you run over a bump at ~20mph. 700C wheels are doing about 5 revolutions per second, and the bike will go up (and maybe down again) in something of the order of 100 to 200mm of distance, or about 1/100th or 1/50th of a second. I suspect that the forces required to do this are somewhat larger than 50kg and maybe the wheel deflections are larger too.

On the second point the tyre, the wheel, the fork(or frame), and the handlebars(or saddle) are each a spring in series with the next spring. The mass is distributed between these parts too. The behaviour of such systems is complicated; each element has its own resonant frequency and impulses introduced at one end of the system will pass through in various different ways depending on how the system reacts as well as the nature of the impulse.

So maybe, if a flexible rim deflects twice as much as a stiff one, you mightn't expect to 'feel the difference in the deflection' per se but if that change is accompanied by a x2 change in the resonant frequency of part of the system, it might alter what kinds of vibrations are passed through to the handlebars/saddle and are then felt by the rider.

-just a thought, anyway....

cheers

[531colin]

........Dear Colin.
Have you actually tried to build the same wheel with a different rim, as I did?
Do it, then we'll talk again. Thanks

More times than you have had a hot dinner.

[531colin]

so one can assume then, that the TB14, lovely tho it maybe, is not 3 x better than the LX17, and also about 75 grams a wheel lighter. so which to choose. I have sent an e-mail to spa, and awaiting 'JOHN ' to reply ( its only been a week so shouldn't be long now )

Spa sell Archetype, not sure about any others?

[iow]

If I had wheels with failed A319s in, I might well choose to rebuild (using the same spokes) with
LX17 (if the original spokes were long enough; do check but I think you might need another 1.5mm per spoke)
or (if another 100g rim weight would be OK) Sputniks (which use a spoke just a gnats shorter I think).

to be fair, the A319 failure was more than likely due to excessive spoke tension. I don't know the actual tension figure, but I used a park TM1 tension meter to lace in the new TB14's making sure I didn't exceed h plus son's 110 kgf recommendation and was surprised how 'soft' 110 kgf feels compared to my previous 'feels about right' method.

[PH]

Back to the OP. There's a lot of recommendations for heavy rims where a lot of that weight seems to be the braking surface. I though part of the benefit of disk brakes was that you didn't need that weight? Are there not disk specific rims that offer the same strength at a lower weight?

[Brucey]

to be fair, the A319 failure was more than likely due to excessive spoke tension. I don't know the actual tension figure, but I used a park TM1 tension meter to lace in the new TB14's making sure I didn't exceed h plus son's 110 kgf recommendation and was surprised how 'soft' 110 kgf feels compared to my previous 'feels about right' method.

I think this happens often. IIRC the tension limit on Mavic rims is less than that of the TB14s too!

FWIW I think there are a lot of rims that (if you respect the tension limits of the rim) can't be built for strong riders without the NDS nipples being at risk of loosening in service. Some wheelbuilders leave those dry (-that they might bind in time, but lubricate all the others) and some use threadlock on them.

cheers

[yostumpy]

Back to the OP. There's a lot of recommendations for heavy rims where a lot of that weight seems to be the braking surface. I though part of the benefit of disk brakes was that you didn't need that weight? Are there not disk specific rims that offer the same strength at a lower weight?

Yes I'm sure there are loads. My Ridgeback world Panarama Deluxe can with 32/32 wheels with a semi aero Alex rim . I have put a ' flat' in the rear rim, so will need a new one. Being 14 st plus, and 6'2", I think a whole new wheel is best with 36. But you cant get these rims now, and they do seem very hard, maybe the aero shape. So on the front the wheel is fine, but I have a disk schmidt dyno hub to put into a wheel. So really I'm looking for a 32 front rim, and a 36 rear disc wheel, with matching rims, that aren't aero shape, coz I hate the look of them. The TB 14 is not THAT much heavier than some disc rims, and they look nice. BTW, didn't mean to start an argument, but my semi aero disc wheels feel more wooden than my Chrinas.

[Samuel D]

There's a lot of recommendations for heavy rims where a lot of that weight seems to be the braking surface.

It depends what you mean by “a lot”, but if you look at the cross section of this TB14, for example, it seems the great majority of the weight lies elsewhere than the braking surface. Consider too that even disc-brake rims need some metal where a rim-brake rim is reinforced to accommodate wear.

Perhaps there are other structural or aerodynamic benefits to not having to make approximately parallel braking surfaces.

[Brucey]

Back to the OP. There's a lot of recommendations for heavy rims where a lot of that weight seems to be the braking surface....

I think that this particular pudding is one that is rather over-egged by some folk. A realistic estimate for the 'extra weight of a brake track' in a moderately lightweight 622 rim (based on, say, Mavic's usual designs) would be a little over 40g. [A disc compatible hub will often carry about the same amount of weight in its mount...] If you were to have a brake track that had the potential for over double the amount of wear in a Mavic rim (which would very much be the exception in modern rims) then about 90g per rim is possible.

Note also that it is presumably tempting to think of this as 'extra weight for no benefit' but this extra material always strengthens the rim (whilst it is present...). It mightn't be the most efficient way to strengthen a rim, but it doesn't have zero effect.

In proportion to the amount there are in use, I've seen many more disc-specific rims crack in recent years than rim brake rims. Very many disc-specific rims seem very much underbuilt for the task in hand, and are presumably specced this way in a desperate bid to compensate for the weight of the rest of the brake system.

I'm inclined to the view that there are good rims and bad rims, and some of the good rims are a little bit stronger/heavier because they also have a brake track on them.

cheers

[mig]

for what proportion of a ride is rim weight a factor? accelerating, climbing.
seems to me that once the wheel is up to speed then it doesn't really matter if it carries a little extra ballast for everyday riding.

strangely in some 40 years of riding i've never once cracked a rim. i must be doing something right but i don't know for sure what it is!

[531colin]

I struggle with this whole argument because on the one hand I know what Colin says is true, yet wheels appear to feel different to me, too.

Thinking out loud here, what if the loads are much more than 50kg? What does 'the system' actually look like that passes road bumps into the handlebars?

On the first point suppose you run over a bump at ~20mph. 700C wheels are doing about 5 revolutions per second, and the bike will go up (and maybe down again) in something of the order of 100 to 200mm of distance, or about 1/100th or 1/50th of a second. I suspect that the forces required to do this are somewhat larger than 50kg and maybe the wheel deflections are larger too.

On the second point the tyre, the wheel, the fork(or frame), and the handlebars(or saddle) are each a spring in series with the next spring. The mass is distributed between these parts too. The behaviour of such systems is complicated; each element has its own resonant frequency and impulses introduced at one end of the system will pass through in various different ways depending on how the system reacts as well as the nature of the impulse.

So maybe, if a flexible rim deflects twice as much as a stiff one, you mightn't expect to 'feel the difference in the deflection' per se but if that change is accompanied by a x2 change in the resonant frequency of part of the system, it might alter what kinds of vibrations are passed through to the handlebars/saddle and are then felt by the rider.

-just a thought, anyway....

cheers

I imagine that 50Kg was simply a load that Brandt could use in his test rig. Even if real life loads over a bump were 4 times that, a vertical wheel deflection of 4 times 0.15mm still isn't a lot.
All the bits in the system will flex in response to a bump, lets have a stab at putting them in order of which flexes the most to which flexes the least.
My guess;.......saddle /tyre / fork / handlebar / frame / wheel .......
I think the wheels are down there among the least vertically compliant things in the system, and it seems perverse (to me) to go looking for "improvements in comfort" from the wheels.
What feels good riding your bike is notoriously subjective....my bike goes much better when its clean and the sun is out. Some say their bike feels much faster without mudguards. Jeremy Clarkson says red cars are faster.
I think your light wheels feel better because you put them in when you expect to have a good day, and also you expect them to feel better.

[Gattonero]

........Dear Colin.
Have you actually tried to build the same wheel with a different rim, as I did?
Do it, then we'll talk again. Thanks

More times than you have had a hot dinner.

Thanks for trying to guess my dinner. You were wrong tho, and ultimately this unwanted answer didn't contribute to the discussion.
So you've tried to build the same wheel with TB14 and Archetype, yes? No difference you say? Don't want to sound rude, but are you sure there wasn't something preventing you to feel that difference? We're talking of the same exactly setup here, on a well known bike.
I know it may sound strange to you, but things do react different on the bike, wheels like tyres and other stuff.
Of course, we're talking of an absolute value, surely may not be any interest for the average user that rides at its own average pace.

When you say "What feels good riding your bike is notoriously subjective....my bike goes much better when its clean and the sun is out. Some say their bike feels much faster without mudguards. Jeremy Clarkson says red cars are faster.
I think your light wheels feel better because you put them in when you expect to have a good day, and also you expect them to feel better" it all sounds to me like you don't think there is a stiff wheel and a more forgiving wheel. It's all the same, it's all marketing then?

[Gattonero]

...

On the second point the tyre, the wheel, the fork(or frame), and the handlebars(or saddle) are each a spring in series with the next spring. The mass is distributed between these parts too. The behaviour of such systems is complicated; each element has its own resonant frequency and impulses introduced at one end of the system will pass through in various different ways depending on how the system reacts as well as the nature of the impulse.

So maybe, if a flexible rim deflects twice as much as a stiff one, you mightn't expect to 'feel the difference in the deflection' per se but if that change is accompanied by a x2 change in the resonant frequency of part of the system, it might alter what kinds of vibrations are passed through to the handlebars/saddle and are then felt by the rider.

-just a thought, anyway....

cheers

Interesting points.
All sounds right, I would add that some components may mask the way the next would act. For instance, a 1.5" tyre at 70psi would act a lot different from a 23mm road tyre at 90psi, I would be the first one not bothering with the way the wheel does feel.

[yostumpy]

currently running TB14 rims on my spa audax combined with miche rg2 hubs and dt revolution spokes - they built up easily (h plus son advised a maximum spoke tension of 110 kgf) and weighed in at 498 g each. the rims replaced a pair of mavic A319 rims which cracked around the spoke holes after 6k miles.
they've only done 2k miles so far, so long term durability is unknown, but brake track wear has been minimal (c. 1.45mm wall thickness when new).
I went for the grey (hard anno) which to my eye looks great.
value is a personal thing - I paid £45.00 a rim from hubjub. do they perform better than a £17.00 rim? probably not, but the look and quality of finish of the rims is second to none imho. money well spent.

What is tyre fitting like, good, avg , or very tight., thanks.