Author Topic: New rim on rear rohloff wheel  (Read 497 times)

ourclarioncall

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New rim on rear rohloff wheel
« on: December 23, 2020, 01:14:24 AM »
If you had normal Andra 30 rims (not CSS) what happens when they wear down ? Do you have to buy a new rim and get somebody to take your rohloff out of the old wheel and build it into a new one ?

And if so , how long to standard Andra 30 rims last ? Probably a hard question to answer

If it would be less than 5 years then I think I would be more inclined to go with CSS rims for less fuss

Danneaux

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Re: New rim on rear rohloff wheel
« Reply #1 on: December 23, 2020, 02:49:49 AM »
Quote
If you had normal Andra 30 rims (not CSS) what happens when they wear down ? Do you have to buy a new rim and get somebody to take your rohloff out of the old wheel and build it into a new one ?
Yep, rebuild with a new rim and spokes or simply do a rim swap as with any rim that has worn beyond specs. The Andra rims have a hollow section behind the braking surface. When that wears through, you will know it and the remaining "C"-shaped section of rim surrounding this wear groove will keep the rim together for a little while till replacement (say, on a tour). However, it pays to periodically check your braking tracks for excessive wear before they get to that point. A straightedge held vertically alongside the rim's brake track will reveal any concavity.
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And if so , how long to standard Andra 30 rims last ? Probably a hard question to answer
Yes, a difficult thing to answer because it comes down to braking habits, terrain, and road surface. If you ride in a lot of grit and dirt, the brake pads will wear the CSS rim sidewalls more quickly than if you only ride on pavement. Mileage (rather than time alone) is a huge determinant.
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If it would be less than 5 years then I think I would be more inclined to go with CSS rims for less fuss
The CSS rims are not so available as in the past. Also, with continued use the sidewalls can become polished and stopping can become longer and more iffy in the wet. A change of pads can help for awhile. Also, some folks find certain combinations of pads/CSS rims are noisy and produce loud squealing when braking In that case, a little dirt on the braking track can reduce the noise for awhile.

I chose to go with conventional Andras on the three bikes I own that use them. I prefer the braking characteristics and have built several hundred wheels, so a rim swap/wheel rebuild is no deterrent for me.

Best,

Dan.
« Last Edit: December 23, 2020, 02:51:29 AM by Danneaux »

PH

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Re: New rim on rear rohloff wheel
« Reply #2 on: December 23, 2020, 12:10:38 PM »
The only argument against a CSS rim is that some find the braking to be not as good as with a standard aluminium rim, that hasn't been my experience, I don't know why there's the variation, though I respect that some others have found it so. Well, there's also the price, but the longevity, accidents permitting, should make it better long term value.
So bearing that in mind, and also that around 80% of your braking is provided by the front brake, and that not rebuilding Rohloff wheels is good for their durability, and the lack of wheel builders with Rohloff experience... It would seem to make sense to have a rear wheel that needed infrequent rebuilding, which means disc or CSS, regardless of the braking you choose for the front.
Rebuilding a wheel with a rim of the same ERD isn't complicated, though you may not wish to do it yourself on such an expensive hub.  Professional wheel builders have their own ideas, and there's a surprising amount of variation.   What you want to avoid (I learnt this from experience) is to be rebuilding the wheel any different to the way it was originally built, that includes the same spoke pattern, same rim size and same tensions. Sometimes the only way to be sure of those things is to either return it to the original wheel builder, or do it yourself.

steve216c

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Re: New rim on rear rohloff wheel
« Reply #3 on: December 23, 2020, 05:43:53 PM »
Rim wear is a factor on all rim brands. And rim wear is not only cause of death of a wheel. I’ve braked through a couple of rims over the years, but I’ve damaged rims beyond repair through bad buckles or where rim has cracked where spoke should be holding and where the rim wear was relatively low. CSS rims will not protect you from the latter 2 situations.
How long a wheel lasts is very much dependent on riding conditions and rider style. My current daily commute of around 20 miles a day sees brake pads lasting 3000-4000 or more km because I have long stretches without needing to stop. I previously rode through the city and had 23 sets of traffic lights to contend with, and where I had to brake often. 2000km on a set of brakes was about all I could reasonably expect. The increased need to brake will inevitably wear the rims faster. That, and dirt/grit etc speeding wear too.
There is no golden life expectancy on wear or how long a wheel will last.
On my old city commute (lots of brake wear) on mostly Rigida/Ryde Zac19 wheels I would expect at least 10,000km of use on non CSS rims. But this could be potentially much higher depending on keeping brakes serviced and pads replaced before grit gets embedded and increases wear.

I first took steps to rebuild my own wheels by buying replacement rims of same model. Loosening spokes on old wheel first to have enough play, I would lay new rim against old then transpose a spoke at a time from old rim to the next while still fixed to the hub. At the end the old rim is released from hub and new rim is threaded exactly the same as originally. Tightening the spokes evenly is not rocket science, but does require patience. It is rewarding once done as a couple of hours DIY is better than a couple of days having bike shop to it for you. Getting spoke tension spot on may require checking and adjusting of spokes as you go, but not as time consuming as rim transfer.
Rebuilding wheel from scratch requires a bit more concentration to follow spoke lacing guides (e.g. from Sheldon Brown’s site) but after a couple of successful attempts as above I had confidence enough to manage that too.
I cannot yet comment on longevity of Andra 30 rims, but I am about to build a brand new hub dynamo wheel with Andra rim. Ask me in 10,000km how the rim wear looks.
If only my bike shed were bigger on the inside...

GamblerGORD649

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Re: New rim on rear rohloff wheel
« Reply #4 on: December 23, 2020, 06:20:05 PM »
WTF ... Why are you considering gRim brakes now?? It's Fred Flintstone technology. LOL
It's a hell of a lot easier to carry spare disc pads that should get at least 6,000 miles.
My SA drum brake front wheel has ZERO wear in 27,000 miles.
If 36 mm tyres, Velocity Dyad is 100% the rim to get. Wider tyres need the other Velocity rims.
« Last Edit: December 23, 2020, 07:06:13 PM by GamblerGORD649 »

ourclarioncall

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Re: New rim on rear rohloff wheel
« Reply #5 on: December 23, 2020, 07:06:04 PM »
Brilliant replies guys

Loving the detail

Grim brakes gave me a smile 😄

I bin using my left brake my whole life, I bin doing it all wrong lol

Will comment more  later after I eat my pizza 🍕

PH

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Re: New rim on rear rohloff wheel
« Reply #6 on: December 24, 2020, 10:00:08 PM »
I bin using my left brake my whole life, I bin doing it all wrong lol
Ha!  Apologies I didn't mean to suggest anyone was doing it wrong... I maybe could have worded it better, of course 100% of your braking comes from whatever brake you apply!  The idea that 80% comes from the front is based on the optimal braking that's available where conditions permit.  I was out this morning and the ground looked slippery in places, I don't think I touched the front brake, though had I needed to make a sudden stop I'd have been relying on it.

ourclarioncall

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Re: New rim on rear rohloff wheel
« Reply #7 on: December 24, 2020, 10:10:51 PM »
Ha, no worries, I find it very interesting actually. Not sure why I never use the front  🤔

Maybe it because I spent my childhood pulling skids round corners or on wet grass.

Or could be coz I got a road bike when I was about 9 or 10 and went over the handlebars coz of the efficient front brake.

I just watched a vid recently on how to do an emergency stop on a road bike at high speed and the pulled both brakes whilst putting there body weight backwards behind the seat. There were also testing rim brakes v discs.

So what’s the scoop ? How are you supposed to brake ? I want to learn more about this

I suppose on a rohloff equipped bike it would aid in rim longevity and less faffing around if you used the front brakes the majority of the time so the rear rim and brake wears much slower

PH

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Re: New rim on rear rohloff wheel
« Reply #8 on: December 24, 2020, 10:56:00 PM »
So what’s the scoop ? How are you supposed to brake ? I want to learn more about this
Best to read plenty, try the different techniques in some wide open space and deduce what works best for you.
When I learnt to ride a motorbike, this was so thoroughly drummed into me, I doubt I could change if I wanted to:
Start to squeeze the front brake, when it bites start applying the rear, as that bites increase the front.  That happens quicker than you can read it!
This might be an interesting starting point with your reading
https://www.renehersecycles.com/how-to-brake-on-a-bicycle/

ourclarioncall

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Re: New rim on rear rohloff wheel
« Reply #9 on: December 25, 2020, 04:33:57 PM »
I wish I had been taught how to ride a motorbike. I started getting over confident on one when I was a teenager. Wasn’t wearing a helmet. Front wheel went down into a rut a tractor had made. Fell on my face and broke my nose badly, had to go to hospital for an operation. Won’t do that again!

I really enjoyed that link about breaking, and reading through the comments was great fun. I never got through them all last night as I had to do Santa duty but wil go back and Polish them off. Really making me think 🤔

JohnR

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Re: New rim on rear rohloff wheel
« Reply #10 on: December 25, 2020, 10:34:12 PM »
Ha, no worries, I find it very interesting actually. Not sure why I never use the front  🤔

Maybe it because I spent my childhood pulling skids round corners or on wet grass.

Or could be coz I got a road bike when I was about 9 or 10 and went over the handlebars coz of the efficient front brake.
When I first got onto a bicycle I was warned to go easy with the front brake to avoid the risk of going over the handlebars. That habit has persisted although I often use both brakes (depending on speed and gradient) with the back being applied slightly before the front one.

It's easier to survive a rear wheel skid than a front wheel skid. Yesterday I was going down a hill on a quiet narrow road where there were two people walking in the same direction as me and effectively using the whole road. I slowed down and what I thought was my fairly loud bell several times with no effect so I had to jam on the brakes and felt/heard the rear wheel skid (I was in the middle of the road aiming for the gap between the people and there's a layer of fine gravel and muck in the middle where the vehicle wheels never run). It was the noise of the skid which alerted the pedestrians to my approach. One of those days when I would have liked an air horn more appropriate for African donkeys - most pedestrians respond to, and appreciate, a modest warning by a bell but something louder is needed for those who seem to be hard of hearing (many have their ears blocked with earphones). Last year I had a front wheel skid (the front wheel got onto some moss on the outside of a bend) which put me + bike on the ground with torn trousers and skin. I don't want to experience that again.

ourclarioncall

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Re: New rim on rear rohloff wheel
« Reply #11 on: December 26, 2020, 02:56:58 AM »
On the braking issue

What about the effectiveness and or contribution of the old jump of your seat and dig your heels or trainers rather into the ground for a rapid slow down? Crude? But maybe effective ? I found it quite effective in my youth and felt pretty in control with both hands on and both feet planted. Times where I never had any brakes and had to create methods of slowing down such as moving onto to rougher terrain to create more resistance when my speed was building up too much. Or using my trainer as a brake on the edge of the wheel , or dragging one or two feet on the ground. Lack of brakes fairly heightens your awareness for danger and in a funny way increases your skill level and awareness. . Lot of variables I suppose such as speed, bike type , clothing , weather.

I was thinking about this in response to a comment that was not too keen on the methods of pushing your body back behind the seat . I can see his point how this might not be the most practical or realistic method in an emergency situation .... for the average Joe who doesn’t spend time working on their breaking skills.

Just thinking about what happens in real life. I guess habits are formed early when riding. Folks tend to mount and dismount bikes in a variety of ways and respond differently to dangerous situations.

I guess it really takes a bit of training (or self discovery of what works ) to drill methods and habits into you

In the last year or so I put my sons bike seat up really high to show him the benefits of getting his legs almost straight, but he was a little scared, of falling off I suppose. Hence in come the crude methods of showing them how to get off the bike such as “just stick your left leg out and let your bike fall left and your foot will just plant on the ground and catch you , youl never fall or hurt yourself.” Or sit up off your seat and move your body over the middle of the top bar and just slowly brake whilst keeping your balance then you can simply just stand step off the pedals onto the floor”


steve216c

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Re: New rim on rear rohloff wheel
« Reply #12 on: January 11, 2021, 02:12:55 PM »
On the braking issue

What about the effectiveness and or contribution of the old jump of your seat and dig your heels or trainers rather into the ground for a rapid slow down? Crude? But maybe effective ? I found it quite effective in my youth and felt pretty in control with both hands on and both feet planted.

Hmmm... seriously? In my youth I weighed far less so the momentum and the riding position on a Raleigh Chopper / Grifter or BMX might have allowed for safer braking 'a-la-ped' than a typical 26" or 28" adult bike these days would afford. Use your feet if you like, but don't be surprised if your pedals or crank whack into your calves/ankles if that is your first choice of braking.  Even Fred Flintstone could stop his car with bare feet- but I wouldn't want to trade that method to save on using ABS...

Each of my 3 bikes brakes differently. Not just the stopping power of V brakes vs hydraulic Magura Rim brakes- but with their center of gravity too. But ride regularly and do the occasional controlled emergency stop and you'll know quickly how best to stop your steed so that it is an autopilot reaction when you need to do it in an emergency. Even learning how to fall from a bike might save your life or prevent more serious injuries. But brakes are there for a good reason and whatever brakes you decide to order- learn to use them through controlled stops- and consider the Fred Flintstone feet down as better assigned to youthful memories than as best way to stop your bike in 99% of usual cases.

If only my bike shed were bigger on the inside...