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650B V 700C Dynamo

by AndyH01
Wed, Aug 15, 2018 14:56
4

For about 5 years upto about 2 years ago, I've done a short 5 mile each way commute and due to changes to my job, I'm hoping to have a 10-15 mile each way commute, mostly on NCN/cycle paths and road, which I'm hoping will take around an hour door to door.

I also do a bit of recorational/family cycling with two young boys 5 & 10 around parks few feilds etc.

I'm pritty much decided on the new bike, Mason Bokeh (I'm also tempted with the resolute steel) but prefer the versaltility of the option of wider tyres.

As the main purpose is the commute I'd be going for a light package, with a Son Delux hub I just can't decide whether to stick with 700c or try 650b wheels?

I'v done some reading and understand the overall diameter are similar and that 650B spin up to speed quicker and lighter than 700c but may feel a bit sluggish on road and as slightly  less efficent and slow down quicker.

I've had 26'er and 29'er mountin bike with wider knobbly tyres which were just knackering and slow on the road. 

I'm not planning to do lots of proper off road stuff and think something like 700cX35 or 40 be fine and allow a bit of off roading.

My previous road bike was 700X23 then 25 from 120psi to around 90psi and I didn't really notice any difference in comfort or effienciency and never had tubeless, with low pressure, but always understood more contact patch the higher the resistence, so not sure how much difference a 650b would make with a wider softer tyre.

I also think as dynmano hub front wheel, a smaller, 650b wheel spinning more/faster as I understand would be more efficenent.

It probably won't be until March next year, so I could start with 700c and come next winter go for a set of 650b and swap between the two ?

I also can't decide what size tyre or pressure be best for both wheels?

Any advice? 

Thanks

Andy 

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4 comments

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madcarew | 5 years ago
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Truly Andy, you're over thinking this. There is a 6% difference in the  diameter of the wheels. In a blindfold test I guarantee no-one will tell the difference with the same size tyres on. The 650B will spin 6% faster at the same speed, so your dynamo will get brighter quicker.

Knobbly tyres are slow mostly because of the aerodynamic drag. Get smooth tyres and you'll be hard pressed to tell the difference. Run the tyres as hard or soft as you like, but know that apart from comfort it won't make a 1 min difference in your commute.

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AndyH01 | 5 years ago
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Hey Dr_Lax did you notice any difference in the efficency of the dynmano on 650b v 700c such as brightness or if charging as I read somewhere that altough the overall sizing are simalar the 650b would of "traveled further"/turned more times compared to the 700c for the same distance and the 650b spn fastar?

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kil0ran | 5 years ago
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I commuted on 700c wheels with a Shutter Precision dynohub for a couple of years. Usually around 15-30 miles per day depending on route/weather. I ran 32mm GravelKing SKs because part of the route had the option for hard-packed gravel and the whole setup was efficient and fast. Can't remember what pressures but those largely depend on your weight. Certainly will feel luxurious compared to most 25mm tyres. The SKs compared side-by-side with Conti GP 4 seasons were something like 1% slower over a 10 mile stop-free part of my route so negligible difference in the real world. They don't feel draggy on the road. 

Lovely bike the Bokeh - might I also suggest the Shand Stoater, Condor Fratello Disc, or Fairlight Strael? Those three companies are great to deal with, as are Mason. Plenty of choice out there.

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Dr_Lex | 5 years ago
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I have a Bokeh and bought the rolling chassis with Hunt 700c wheels. I had a set of 650b wheels built on a SON dynamo hub and run these with 35mm Schwalbe G-Ones during GMT; the 700c with 28mm Schwalbe Ones during BST. Both are run tubed and in my experience in the last year, the 650b aren’t much slower - around 2 mins on an hour commute. I have some meatier tyres (Thunder Burt & Racing Ralph) for true rough stuff with the 650b set, but not had an opportunity to test them. If you want to keep to a budget, start with one set of wheels.

Terrific bike; Dom and his crew are a pleasure to deal with - heartily recommend one.

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