Power is simply RPM*Torque in the same way that work done = force*distance. Simple Physics.
My legs work better at higher torque and lower RPM it seems. I was not good when I tried the velodrome, that is all about high RPM.
Continued Failure of components on Ultegra Di2 component set
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My legs work better at higher torque and lower RPM it seems. I was not good when I tried the velodrome, that is all about high RPM.
Yellow Saddle
Guru
- Location
- Loch side.
I can understand that you feel frustrated but I think you are to blame for most of these problems.
The crank shaft broke in reverse, in other words, from frequently standing on the pedals - left foot back and hopping obstables. My guess is that you are a hotfoot instead of goofy, like most of us. It is a skateboarding/snowboarding concept but it has bearing on how we stand on the pedals. In the early 1990s had an engineering failure with Octalink BBs because Shimano didn't consider the concept. Have someone help you figure out if you are (foot) biased as I think you are.
The frame. I blame you for buying titanium and thinking it is stronger than other frames. Titanium is touted as the moder metal and if you look at the lab figures for strength, it is indeed very strong. However, it doesn't fail in the two most commonly measured modes of strength namely tensile or compressive. It fail in brittle fracture, emanating from the weld. That crack is not a result of front-end collision but from your weight bending the fork forwards and frame downwards. The crack started at a stress riser under at the head tube weld. I would recommend that you are a good candidate for a carbon frame. However, even an aluminium frame would be better that a Ti one for longevity.
Your FD. In short, unsympathetic gear changes. You are attempting to change down whilst still powering the chain. You have to learn to "feather" the pedals when shifting. Just because the electric system can shift under power, it doesn't mean it is a good thing to do.
Chainring failure. Again, shifting under power. If you apply heavy force whilst shifting, you will have problems. I can see from the position of the crank that the crack developed in the region that is stressed when you push your right leg down. The chainring and FD failures are thus related. I am surprised at the size differential between big and small ring? Is that setup standard?
Hub failure. It is the inboard bearing that broke when the inner race cracked and broke in two. I can't quite explain that one other than to point out the fretting damage on the hub axle directly underneath the inboard bearing. This shows that you do apply high force to the cranks. Remember, that the axle has to resist all the chain tension and it flexes right there. I have no advice because I don't know of anyone making a hub with an oversize steel axle. I suspect 10mm steel axles won't do the job.
Your failures have nothing to do with maintenance. However, you need to attend a few equipment sympathy therapy sessions.
Thanks for the reply.
You are completely wrong about me "hopping" BTW - I very rarely even drop down off a kerb onto the road and when I do it I go very slowly one wheel at a time.
Since I bought the frame a few people have told me that it was the wrong choice. Unfortunately I explained exactly the riding I was going to be doing and 2 different bike shops were very happy to sell me a bike.
The reason that I went for a Ti frame is because I wanted Di2, Hydro disk brakes and a rear pannier. That does not exist on a carbon bike.
The hub failure WAS due to a lack of maintenance apparently. It's a hope hub and I've been told that they need cleaning out and re-greasing every now and then. The bike shop that regularly has the bike told me that. Apparently I need to specifically tell them to do this every few months rather than them doing as part of normal servicing.
The chainrings are perfectly normal 52-36 rings. Nothing special.
Yellow Saddle
Guru
- Location
- Loch side.
Thanks for the reply.
You are completely wrong about me "hopping" BTW - I very rarely even drop down off a kerb onto the road and when I do it I go very slowly one wheel at a time.[/QUOTE]
I'll accept that. But just check with which foot forward you descend or rest. It may have bearing on the situation. It may also be that Dura Ace uses a thinner crank shaft.
Since I bought the frame a few people have told me that it was the wrong choice. Unfortunately I explained exactly the riding I was going to be doing and 2 different bike shops were very happy to sell me a bike. [/QUOTE]
You sound surprised that 2 different bike shops were prepared to sell you an expensive frame?
Here's your next bike, just spec Di2
That's just plain nonsense. The only maintenance that can be done on those hubs is a pawl service and bearing replacement. Whilst regularly replacing all bearings sounds like a good idea, it merely introduces new risks each time. A bearing does not crack like that from lack of maintenance. It cracks because of a fault in the bearing itself. If you still have the bits we can look at it. Dud bearings do exist as with any mass-manufactured products. Such faults show up relatively quickly during use and once they have lived a certain time, they won't fail like that but wear out. By regularly replacing them you are simply re-introducing a new risk each time.
You were just unlucky with that hub. It won't happen again.
OK, it just look a bit strange but has no bearing on the issue.[/QUOTE]
You are completely wrong about me "hopping" BTW - I very rarely even drop down off a kerb onto the road and when I do it I go very slowly one wheel at a time.[/QUOTE]
I'll accept that. But just check with which foot forward you descend or rest. It may have bearing on the situation. It may also be that Dura Ace uses a thinner crank shaft.
Since I bought the frame a few people have told me that it was the wrong choice. Unfortunately I explained exactly the riding I was going to be doing and 2 different bike shops were very happy to sell me a bike. [/QUOTE]
You sound surprised that 2 different bike shops were prepared to sell you an expensive frame?
I understand that choices are limited with that setup.
Here's your next bike, just spec Di2
That's just plain nonsense. The only maintenance that can be done on those hubs is a pawl service and bearing replacement. Whilst regularly replacing all bearings sounds like a good idea, it merely introduces new risks each time. A bearing does not crack like that from lack of maintenance. It cracks because of a fault in the bearing itself. If you still have the bits we can look at it. Dud bearings do exist as with any mass-manufactured products. Such faults show up relatively quickly during use and once they have lived a certain time, they won't fail like that but wear out. By regularly replacing them you are simply re-introducing a new risk each time.
You were just unlucky with that hub. It won't happen again.
OK, it just look a bit strange but has no bearing on the issue.[/QUOTE]
Dogtrousers
Kilometre nibbler
Frame aside, I have a smalller, but similar list from commensurately smaller mileage. I've gone through drive train components (but not mechs, admittedly) like nobody's business.
I'd put your experience down to a combination of heavy use, bad luck, less than obsessive maintenance, and short working life of components. I suspect Ultegra/di2 is designed with racers/Mamils in mind who will lovingly relube everything after each and every ride and replace things in short order.
How about going for a nice steel frame with hub gears like Alfine or somthing? Just a thought.
I'd put your experience down to a combination of heavy use, bad luck, less than obsessive maintenance, and short working life of components. I suspect Ultegra/di2 is designed with racers/Mamils in mind who will lovingly relube everything after each and every ride and replace things in short order.
How about going for a nice steel frame with hub gears like Alfine or somthing? Just a thought.
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The quoting was a bit messed up there. I don't get what you meant about my next bike...
TBH - I don't really descend or rest much. Very few hills on my route and the ones I have I pedal down. I suppose I coast up to traffic lights but that's it. When waiting at lights I always have the same foot clipped in and the the other on the road.
TBH - I don't really descend or rest much. Very few hills on my route and the ones I have I pedal down. I suppose I coast up to traffic lights but that's it. When waiting at lights I always have the same foot clipped in and the the other on the road.
S-Express
Guest
It's not bonkers, it's basic physics.
If its basic then why do his results differ to mine ?
The fact that a higher RPM produces higher power figures is basic physics...
Yet you say lower RPM produces higher power for you ?
Yellow Saddle
Guru
- Location
- Loch side.
Here's the link I wanted to post.
www.rosebikes.co.uk/products/bikes/trekking/travel/team-dx-cross-randonneur/
S-Express
Guest
How do your results differ?
lower RPM but higher torque.
i.e. I don't spin as fast but I push harder.
power=torque*rpm
so if you increase rpm or torque power goes up
It's going to be a while before I'll be getting another bike but hopefully there will be lots of options when I do!
