Hammer 1 - Belt issues

My Hammer 1 belt snapped about 6 weeks ago. Generic replacement fitted (as I couldn’t find an EU supplier), and all going well up until this mornings “Beech”. A knocking sound started. Stopped immediately, and it appears that the belt is stretched already, so the teeth aren’t meshing correctly at one point on the belt.

I’m not concerned by knocking sound, as that seems to be where it releases by the fly wheel. But it’s not meshing through the resistance unit either. I’m on a recovery week, so will switch to my hybrid rollers for these workouts, but I was hoping to race, in SIM mode, on zwift on Friday. A replacement belt won’t be here by then. So would I be risking any long term damage doing that race?

It was a generic belt, as I was unable to source an official one here in Ireland, or UK, or seemingly in the EU. I’m a bit disappointed with the longevity, given the official one lasted years with no maintenance, and this one barely 6 weeks!

When I checked the belt tensioner, it was quite slack - an inch rather than the 3/4 inch. Would/ could this have contributed to the belt issue this time? Or some fitting fail on the original swap?!

Hi Macy,

Got my replacement belt from Evans Cycles UK, but a quick search shows they don’t appear to sell them anymore.

sales@raleigh.co.uk might be able to help get spares to you, that email address has responded to me in the past, again I would assume they ship to the EU. Saris in the USA always point me in that direction for spares and warranty and they stock all replacement items for the Hammers. Parts list on their site is [here] (https://raleigh.zendesk.com/hc/en-us/articles/360007645618-Saris-Hammer-H2-and-H3-Spare-Part-Codes) for the 9734T Belt,Replacement,Direct Drive,Poly-V

When I swapped mine I did note the belt tension on my H1 was very lose, probably why I got knocking noises every so often. Did tighten to the recommend setting in the kit, off hand I can’t remember what that was.

Unfortunately my original Hammer is currently broke, not the belt as that’s been going strong for 6 months+ since replacement but four flash red LEDs which I’m going to investigate when I have some time at Christmas… I ended up buying a H3

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Yes, Saris pointed me to Raleigh, and I am awaiting a response. It’s not on their website to purchase.

I tightened it as per the instructions when I fitted the new belt, but never checked it since until the issue.

I’m unsure whether to use it and hope it settles down, trim the teeth that are out of line so it’s smooth through the resistance unit or just leave it. Waiting for the a generic, from the US, in Black Friday period, in the middle of a pandemic has definitely affected the delivery times since the last order!

The lack of available EU spares will probably influence my next smart turbo purchase to be honest.

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I did get a reply a while back when I contacted them over a noise in 2019, I believed it might have been the belt but at the time it ended up not being the belt but the chain had lost one of those doughnut links.

Maybe give them a call on their number below?

Raleigh UK Ltd
Church Street
NG16 3HT
01773 532 600

The reply I got at the time (4 days after my email then replies were pretty fast) from Raleigh UK said the following “I read your email regarding your hammer trainer, we are waiting for belts to arrive 9th of April part code is CYSP24473. have you checked the free hub? look at the pawls check for damage and spring tension too. Part code CYSP24471.”

I ended up going with a H3 because of my experience with H1, I use my trainer almost daily, only issue was a belt after 2.2 years of continuous usage, it was hammered! The red LED thing is annoying but I hope to fix that with my third line electronic knowledge, expect it to be a sensor open circuit or something, if not I have spares or I might just fit some sort of variable resistance knob!

Do find calling Saris in the USA number very helpful, I use one of those 0.1p minute phone numbers so not really a cost, and you get good advice, also no call queue!

I do get the lack of available spares to just order from a website in the UK annoying , I did consider another too but I went with what I know it’s solid and works. Warranty is fair as well, One year for belt and two years for electrics. If this H3 lasts as long I’ll be happy, I guess that’s why they got my cash again.

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I’ve been happy up to now, and in fairness, up to the belt snapping I had done zero maintenance on it. I was actually scared to mess with it!

Up until March, mine wasn’t daily use, but has been at 6 days out of 7 since then, and some days were double days.

The irritating thing is I do have access to a US mailing address, but I can’t pay on the Saris site with an Irish card!

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Raleigh came back to me, so part ordered. The website still only gave me a UK address options, so I used a forwarding service I subscribe to and paypal.


Great news, hope it arrives soon and you get another couple of years out of it! :grin:

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Hope its the right part, as they gave me a different number! 2 on the way anyway - official and another generic from the states via amazon.

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From what I can tell its the same part for all three models, though I haven’t opened up the H3 to confirm that, just going by the spare parts code website…

I did quickly swap my cassette by undoing the hub and swapping it across quickly, that was exactly the same, saved a lot of time trying to line up all the different cassette rings and messing with the chain whip etc!

I guess I’ll find out about the belt if I ever have to donates parts from old one to new one, hopefully a task many years from now, unless I can fix and maybe sell it.

The H3 uses a very different belt and related pulleys. H3 is “ribbed” vs “cogged” like the Hammer/H2 belt. The change was made to make the trainer quieter to compete with the Kickr and Neo trainers.

Per the Saris replacement parts page, they offer two different belts:

Hammer/H2 = Cogged

H3 = Ribbed

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That’ll be why I can hear my chain go around now :wink:

Thanks for clarification.

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I just went with what they told me it was anyway! Don’t need the tools, but…

@mcneese.chad any opinion on options I listed to use in the meantime, or just not risk it? I’m tempted to trim the affected teeth, as worst that would happen would be slippage. Where as with them not meshing, the section with the two damaged teeth is “raised” going through the resistance unit (at least on the workbench, unplugged with the fly wheel being hand turned).

It looks like the belt stretch only on one side, which I don’t know whether that was a fitting error on my part, or not keeping the tension correct.

Sounds like a poor quality belt and one I would hesitate to use, especially if hacking is needed to run it. May be a non-issue, but I have a hard time trying to use a cheap part that doesn’t work right in light of potential damage to the trainer itself.

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Yes, I tend to agree. I wouldn’t have gone for it in the first place only it was the fastest and easiest option at the time. I’ve been very happy with the Hammer overall, but not convinced by Saris in EU for support, and this is before Brexit!

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Timely topic for me, I’ve been wondering lately about how much longer my belt on the H1 will last, I’ve had it nearly 4 years and I use it 5 days a week year round. I’ll definitely be getting one to have on hand in the event my belt does fail. Not sure if it makes sense to just proactively change it prior to failing, thinking maybe just wait until I have to.

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4 years is great with that usage. Yes I’d get one in stock and wait for failure, that’s if it doesn’t inconvenience you, e.g. during a Zwift race it fails etc.

Do wish I’d opened mine up earlier and checked the tension setting, as I’m sure that contributed to an earlier failure of my belt… it was so loose, made me wonder if it was ever correctly set, or just normal mechanical vibration that made it loosen up.

That’s not good news for a meshing belt. Losing a tooth here or there is usually well-tolerated on such drive systems, in particular with larger pulleys (which engage more teeth), and stretching is to be expected - but your issue “on one point of the belt” sounds like a failure of the belt material. There’s no level of twiddling with teeth that can fix that. This said, while I have no knowledge of this particular trainer, a meshing belt must be kept tensioned correctly, otherwise it will ride up in the pulleys, slip and wear out the teeth. Better quality belts will stretch very little, lower ones (or ones used above rated tension) will stretch a lot more.

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I would order the official spare rather than necessarily change it. That’s my big regret. I’ll be keeping my new generic as a spare as per this experience, while awaiting sourcing official. Really has been a case of “buy cheap buy twice”.

I would check the tension bolt as well, and to do that you’ll have to remove the cover so you can inspect the belt anyway. I don’t know whether the belt snapping can cause damage - for me it was just a complete loss of any resistance (like when you lose your chain outside).

Yes, I agree - just a bit of straw clutching.

So zwift racing on a dumb trainer :thinking: Might be a week to skip…

Again without knowledge of the specific design - generally nothing bad will happen to the mechanism from a belt failure. Resistance will be lost, that’s it. Now if you happened to be standing at high load and mashing the pedals at that time - some parts of your mechanism may get damaged.

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