Wittson Supressio build

[Prawn]

THM brakes are off the bike - replaced by trusty dura ace for the moment. Hopefully I will be able to return them and try out eebrakes.

I’m starting to appreciate the bike’s qualities. It is not as stiff as my tarmac, yet my times up hills are improving. Downhill is where I notice the biggest difference. I’m nervous on steep sections, especially when the road surface is bumpy; the additional damping of ti, together with a slightly slacker head tube angle seem to be helping.

@leicaman, I look forward to seeing your t2 build

[Prawn]

With the dura ace brakes back on the bike, I need to find 160 g elsewhere. Any thought on cranks? EeWings are attractive, especially now that there is a 2x spider available, but the weight saving would be small overall. THM cranks are light, but there is no obvious power metre solution... and I’m a bit put off by my experience with their brakes.

[KCookie]

The THM M3 crank is compatible with a SRM power meter but not cheap at AU $4700, that includes the head unit to.

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[mike]

U need to tighten the front brake. Use wrench to hold nut and use Allen key to tighten bolt. Once tightened it should work like a charm. Thm brake are the best for the weight and superb stopping power

[Prawn]

@Mike, I wish it was that simple. Both were put on per the instructions, that is: Hold the front outer csaptive 'nut' with a spanner and tighten the sleeve nut to 10Nm. The fork is Enve 2.0 so presumably the observide fore/aft movement and brake pulsing was not from there. I could see the caliper arms flex. I tried with two differnt wheels just in case, but saw the same problem. Next, I replaced only the fornt THM caliper with a DuraAce 9100 - which completely eliminated the front brake pulse... but the rear brake pulsed. Finally, I replaced the rear THM with 9100.. all good.

I like the look, weight, and concept of the THM brakes, so any suggestons are welcome as I don't want to give up yet! It would be interesting to know if the new version is any better - mine are new, but previous generation.

[Prawn]

@KCookie, Thanks for the suggestion. M3 with SRM power is (if i've added it up correctly) heavier than DA9100 cranks... and, as you point out, rather expensive.

[KCookie]

Definitely dont get the new version of the brakes, there's been quite a few unhappy customer's. Most send theirs back for a refund.

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[KCookie]

@KCookie, Thanks for the suggestion. M3 with SRM power is (if i've added it up correctly) heavier than DA9100 cranks... and, as you point out, rather expensive.

Not a problem. I actually didn't know that. Definitely dont won't to spend that amount of money to gain weight.

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[mike]

I have never had pulsing on thm brakes. What is your weight? Also make sure brake pads are properly angled and use proper brake pads with wheels. I like swisstop yellow

[RyanH]

M3 with SRM weighs 459g sans rings. It's the same weight as a Cannondale SRM with SiSL2 arms. SRM Origin is roughly 515g. If you want the lightest and just want to see a number without caring much about the accuracy or whether or not that number even shows up sometimes, get a Stages. If you want light and reliable, you'll need to cough up for an SRM. Other options are a THM Clavicula SE with Garmin or Favero pedals.

[Prawn]

I have never had pulsing on thm brakes. What is your weight? Also make sure brake pads are properly angled and use proper brake pads with wheels. I like swisstop yellow

Mike, That’s reassuring. I’m 70kg. I’m using black prince pads (which came with the wheels - DT RRC 32 T). It’s easy to try different pads, so I might grab a set of yellows and see if that helps. Campagnolo pads (Shimano fit) might be worth a try too. Please let me know if you have any advice on the correct amount of toe-in to set, as this is another variable that I haven’t experimented with.

[Prawn]

M3 with SRM weighs 459g sans rings. It's the same weight as a Cannondale SRM with SiSL2 arms. SRM Origin is roughly 515g. If you want the lightest and just want to see a number without caring much about the accuracy or whether or not that number even shows up sometimes, get a Stages. If you want light and reliable, you'll need to cough up for an SRM. Other options are a THM Clavicula SE with Garmin or Favero pedals.

Ryan, thanks for correcting my misunderstanding of the M3 with SRM weight. You make a good point about accuracy - I spent two years trying to train with an old quark power spider only to realise that it was a random number generator! Perhaps the M3 is an investment worth making given its weight and performance. An alternative might be the specialised power cranks at a claimed 440g without rings, although I’m not sure that they would match the bike’s aesthetics or be in the same accuracy/durability league as the SRM. I’m a true believer in Speedplay, so no pedal power meters for me! By the way, your T1SL build looks fabulous and I enjoyed Reading the unfolding story.

[RyanH]

I think the jury is out still on the reliability of the Specialized powermeter. My friend has one and it's a POS but that may just be a bad sample. M3 SRM are extremely expensive. Quarq overall is good until they have water issues which seems to happen without fail after a year or two. I think they got a little heavier but my old Quarq Red compact was 520g and I think the newer ones are claimed at 550g.

Lastly, unless you want to go a step backwards in braking, skip the yellow pads. The only wheels that yellow pads work well with are Mavic, nearly every other pad will perform better than yellow on most wheels. Yellow pads were the very first carbon brake pads...why would you want to revert to those? Campy red pads seem to be a solid all around performer for many wheels.

[mike]

I would press brake levers so pads are contacting rim and then tighten. I am 85 kg and no problems at all with thm original brakes like yours. Also check to see if your carbon spring is damaged or broken which could cause pulsing

[Prawn]

I’ve contacted THM to seek their advice. The problem seems quite clear to me: as the arms flex, the cable tension changes, thereby setting up an oscillation. Haven’t heard back from them, but to be fair I only contacted them on Wednesday.

I’m going to try the aeropod power meter - if it proves to be as good as it seems then the pathway opens up to use THM clavicula cranks (or any other lightweight crank set regardless of whether it has a power meter)