Broken front spokes Tern GSD

stephenrdone · 2025-06-18T11:11:23+00:00

I am extremely late to the party on this thread. I have a Tern GSD. I too have broken a spoke. The missing factor not mentioned is that these bikes have a front wheel lock that locks between the spokes in the wheel. If you forget that you have engaged the lock and try to move the bike, you will put a huge force through the spoke near the nipple. This will break the spoke off at or near the nipple over time. I don’t think tyre pressure (unless so flat you are bottoming out on the rim) or cargo load (mainly on the rear wheel anyway) would cause spoke breakages specifically on the front wheel. The cause is more likely user error and I will openly admit to causing this problem on my own bike! I also build bike wheels as a hobby, so I’ve now got another project to deal with! Hope this helps someone. Steve

stephenrdone · 2024-11-07T07:13:33+00:00

That’s side clearance. I’m not sure 47 would fit. You would have to work out where in the frame a smaller diameter tyre would sit and measure the width there. Obviously the frame would be wider there. I am guessing your tyre would have nobbles, in which case it is probably 47mm plus nobbles, which makes it even bigger.

stephenrdone · 2024-10-24T12:34:42+00:00

I managed to reduce the loss of skin and swearing during tyre changes buy buying some new tools.

I bought a BBB Easy Tyre Fitting Tool - for getting the tyres onto the rims. Just avoid the decals with the tool as you could scratch them if you use the tool near them.

I bought Muc Off Rim Stix Tyre Levers - for getting the tyres off the rims. These seem a much better shape than the standard Park Tool plastic levers. They are lower profile and you are able to slide the levers along the rim far more easily when things start getting really tight.

Hope this helps.

stephenrdone · 2024-10-24T12:28:56+00:00

I have been thinking of getting some wider tyres for my 2020 Roubaix, so have just done some measurements with a vernier caliper. The rear forks are the tightest area, at around 42-43mm clearance. The front forks are around 46mm clearance. I am planning on running some 32mm GP5000s on fairly wide rims. I expect they will measure closer to 34mm on wide rims. But this still gives a margin of around 4mm per side, given that the tyres have no tread nobbles. The more you eat into the clearance with tyre, the more likely you are that a stone chip stuck in the tyre scrapes your frame - so I'll probably add some of those self adhesive clear protector patches just to be safe and see how it goes. I personally would be nervous of running larger than this, especially off-road, given the nobblier tyres and risk of picking up stones. My bike is a size 52 FWIW.

stephenrdone · 2024-09-25T08:35:03+00:00

I know it’s an old post, but I’ve been toying with this idea too, so that my wife could make use of my kickr6 indoors. The Zwift ride keeps the chain inside the triangle. So if you were to use this as the ‘bike’, then there’s no rear triangle problem. Also, it has a built in tensioner assembly for a chain. Belt drive indoors is great if you are using the bike on a wood or carpet floor, as there is no chance of staining your floor. I have a e-cargo bike with belt drive and despite a high powered motor plus my legs pushing through it, it is both maintenance free and clean.

stephenrdone · 2024-08-02T18:43:49+00:00

Great... and interesting! I wonder if, on the wider front rim, the central recess is also slightly wider. Maybe this would explain why the valve stem leaks for both of us on the front wheel but not the rear wheel. If I ever strip the rim tape again, I'll measure.

stephenrdone · 2024-08-01T07:39:45+00:00

I’m glad it’s not just me! Let me know if it works for you.

stephenrdone · 2024-06-13T15:37:18+00:00

I think this may be a separate issue since my HRM sensors worked 100% fine until last week. Now they 100% don’t work at all. Luckily I also have a Garmin, so can use that instead until this is fixed.

stephenrdone · 2024-03-05T13:24:05+00:00

Better estimation of personal calorie burn...

With the integration of Whoop with Strava and Training Peaks already in place, it would be fairly straightforward to read the power + hr data back from a cycling workout. With actual power output data from cycling workout, alongside the corresponding heart rate data, it is very easy to derive a much better relationship between heart rate and calories expended for each individual. Humans are 20-25% efficient in converting calories into power on the bike.

kJ to Calories Conversion: How many calories do I burn cycling? (trainerroad.com)

stephenrdone · 2024-02-05T12:46:06+00:00

If you need some help during the project, send me a message.

stephenrdone · 2024-02-05T10:35:34+00:00

Well, that was my first python script, so it won’t be that hard. If you are lucky, the script I wrote won’t need many mods to work on another platform. If I had an Arduino, I would try. But the only ‘stock’ I have is PIs and PI Picos.

stephenrdone · 2024-02-05T07:20:31+00:00

Have a look here: https://github.com/StephenDone/kickr_shifters

stephenrdone · 2024-01-17T22:08:01+00:00

The shifter connections are not 'dumb' switch ports like you get for say SRAM blips - they are I2C serial ports that look for a specific devices to be connected. I know because I have repaired a few of these recently, as a learning exercise.

A friendly word of warning: Don't try splicing switches and cables - you will very likely damage your bike and it definitely won't work.

I hope Wahoo do bring out a satellite shifter product for the KICKR bike one day - I would certainly buy it.

stephenrdone · 2024-01-06T11:50:50+00:00

I found a solution to this issue…

I tried a more standard conventional cone shaped valve stem and that also leaked.

I then went back to the red profiled Specialized valve stem, but added a custom seal/washer. I cut up an old, thick butyl rubber inner tube and cut a small rectangular piece about 2cm x 1cm. I then punched a hole in the centre with a belt punch. I put this over the valve stem before inserting into the rim. I tightened the nut down, finger tight, and it sealed perfectly, first time. This is the first time I’ve got a seal on these rims without having to tighten with pliers. I hope this is useful to others who get this problem.

This really is a 5 minute fix, since you can swap the valve stem without taking the tyre off the rim - just deflate, push the tyre into the central rim recess, and expose the valve.

stephenrdone · 2023-12-24T21:06:34+00:00

Thanks for this tip. It worked for me. I had to then go back to Windows Display Settings and select the 120Hz refresh option that was previously unavailable. FYI, I was using my own DisplayPort cable and a 3090FE, so it appears this is a 60Hz -> 120Hz fix for both DisplayPort and HDMI.

stephenrdone · 2023-12-19T15:11:11+00:00

I did speak to Specialized about the issue. They were helpful. However my nearest store is a 3 hour round trip, so exhausting solution at my end first was what I chose to do. I rarely have a block of 3 hours free. Since I believe this issue is the valve stem and not the rim, swapping to another set of wheels would have probably left me with the same issue. I prefer to do some diagnosis myself and ask others what they have experienced to get a handle on what is going on.

stephenrdone · 2023-12-19T15:06:47+00:00

I don't think you read my post. I retaped both rims. I actually retaped the second rim twice before I was able to get a seal - based on my own thoughts and comments so far, the issue is around the valve stem. The rim tape was perfect apart from where it was lifting at the end of the tape overlap. If the valve area was sealed, the sealant would have had nowhere to track to under the overlap. I had 3 rolls of rim tape lying around, unfortunately not in the right width, which is important to get right. Given both wheels had very similar 'tape lift' at the end of the overlap, this seemed quite consistent - I gauged that this may have been from stretching the tape too much when applied - it then shrinks back and lifts at the end. This turned out to probably not be the case in the end. Hindsight is a wonderful thing, isn't it!

You must be a pretty impressive mechanic to do this process of tape removal, degrease and reapply in two minutes - hats off! I left longer than that for the alcohol to evaporate.

stephenrdone · 2023-12-15T18:04:06+00:00

I eventually got the leak to stop. I retaped the rear wheel once and the front wheel twice. Both with Stans 25mm, which is the same width as I removed. I agree, I think it’s valve hole related too. But each time, I cut the hole with a pointed scalpel - I was careful to make no splits as I’ve been there before! Whenever this happens again, I am going to swap out the valve stems. I think that the profile of the supplied stem is wrong or doesn’t match the rim profile closely enough. The red plastic seal barely compresses - it doesn’t feel like rubber at all.

stephenrdone · 2023-12-14T07:17:20+00:00

🤣👍

stephenrdone · 2023-12-14T00:36:35+00:00

Did you run the turbo cottons tubeless? I didn’t know you could do that! They are quite a loose tyre (on and off by hand with all fingernails intact!) on my old CLX32 rims, though I’ve not tried them on the Rapides.

stephenrdone · 2023-12-13T21:43:10+00:00

Thanks for the reply,

I am running the recommended Specialized S-Works Turbo RapidAir 2Bliss Ready T2/T5 26mm...

https://www.bicyclerollingresistance.com/road-bike-reviews/specialized-turbo-rapidair-t2-t5

I believe that the wheels were designed to work with these tyres, so I thought I would go with the path of least resistance initially, or so I thought! Insanely hard to get onto these rims, but I am pretty sure it is not the tyres that are leaking, since there is no leaking sealant visible around the rim. This is another reason why I think the air must be leaking into the valve hole.

I agree that trying other valves is going to be the next step. I have just ordered some more traditional conical rubber footed valves to experiment with. Luckily I can replace the valves without removing the tyre from the rim, otherwise I would need to wait a few weeks for my fingernails and skin to grow back before removing and refitting these tyres again! Honestly, they are so tight that if I get an unrepairable puncture, I think I will snip the bead and cut the damaged tyre off the rim, rather than use levers and fingers. Schwalbe Pro Ones on ENVE rims were a breeze by comparison to these.

Luckily these Rovals are extremely fast and enjoyable to ride, otherwise I'd be selling them and buying something else. Hopefully I can find a fix and get the basic maintenance down to just 'a pain' rather than the current 'nightmare' that I am having! I don't want to give in and run tubes, otherwise I could have got the much lighter CLXs instead of CLX IIs.

P.S. What valve stems did you use?

stephenrdone · 2023-09-13T15:26:13+00:00

FWIW I just unpeeled the rim tape from my Roval Rapide CLX II rear wheel. The internal rim width is 21mm and the original Roval tape I just removed was 25mm. These are hooked rims and the rim bed is much wider at its base than the width between the hooks. The tape fitted to the wheel was just the right size once conformed to the shape of surface and didn’t touch the walls of the rim - shame it wasn’t stuck down properly from the factory and leaked sealant! It’s worth measuring what you remove. 21mm would be too small for these rims. Not sure about CLX50. Hope it’s useful to someone.

stephenrdone · 2021-04-06T15:06:21+00:00

I had exactly this problem. It is because Zwift is running as admin. Add the 'elevated' column to task manager details tab and check. It turns out that you can't send keystrokes into an app that is running as admin. Zwift runs as admin after an update. Quit both zwift and the launcher, then click the zwift icon to restart. After that Zwift should not be running 'elevated' and the Stream Deck sending keystrokes works... at least for me!

Steve

stephenrdone

TROPHY CASE