Thorn Cycles Forum

Technical => Wheels, Tyres and Brakes => Topic started by: PH on March 14, 2018, 03:42:49 PM

Title: Benefits of a lighter rim - Mercury
Post by: PH on March 14, 2018, 03:42:49 PM
The Rohloff in my disc brake Mercury came off a rim braked bike and is built on a heavyweight Sputnik rim.  It will in the near future need to be out of service to have an oil leak sorted and I'm wondering how much benefit there would be in having the rim changed at the same time.
Use is commuting, utility, lightweight camping, credit card touring, maybe some Audax, I ride quite a lot of tracks though most of them are better surfaced than some of the country lanes.  Usual tyre size 32 or 35mm, I can't see me using wider or narrower. I'm no lightweight (95 kg) and not a particularly gentle rider.  The Sputnik was chosen for it's longevity and has served me well, though with the disc brake that extra thick braking surface isn't needed.
If I do change - any recommendations?  I'd be tempted to use a rim that could used with a rim brake, both for the versatility and also as a better match for the front (Grizzly) though I'm open to persuasion.
Thanks
Title: Re: Benefits of a lighter rim - Mercury
Post by: jags on March 14, 2018, 04:39:59 PM
Mavic open pro are great i's what i use on my audax .

anto
Title: Re: Benefits of a lighter rim - Mercury
Post by: mickeg on March 14, 2018, 08:37:37 PM
If I recall correctly, Mercury is 700c.

Last spring when I built up my Titanium bike that has rim brake on front and disc on rear, I used Velocity Dyad on both front and rear.  This bike is a derailleur bike, I used 32 spoke front and 36 rear.  Velocity would not have the special drilling that Ryde has for a Rohloff wheel however, not sure if that is a concern or not for you.
http://www.velocityusa.com/product/rims/dyad-622

They have worked quite well for me.  I mostly ride that bike without a load on it, but I did a five day loaded tour with four panniers.  I weigh about 80 kg.  I have only used 37mm tires so far, but might try some 32mm tires this year.

Title: Re: Benefits of a lighter rim - Mercury
Post by: PH on March 15, 2018, 04:16:09 PM
Thanks both.
Yes Open pros are nice, I've had them on an Audax bike and they were perfect with 28mm tyres, I'm not sure I'd want to go much wider so probably not the best choice for this bike.
The Velocity rims look interesting, does the higher profile make any difference? 
I should have added that if I do this it'll be by SJS, so the choice will be something from what they stock.
As much as the choice of rim, I'm trying to convince myself how much difference a 200g lighter rim will make, one day telling myself it'll make a huge difference, the next that I probably won't notice...
Of course if I was starting from scratch it'd be a no brainer, I wouldn't have chosen a sputnik, so maybe it should be my aim to get this bike to what it would have been if I had.
Title: Re: Benefits of a lighter rim - Mercury
Post by: jags on March 15, 2018, 05:38:45 PM
you might as well go as light as possible make cycling easier ;)
i remember i got the schwalble marathon plus wire bead tyres  in the post i could have cried  :'( :'( they weighed a ton i soon got rid of them weigh matters  for us cyclists  lighter the better  imho.
Title: Re: Benefits of a lighter rim - Mercury
Post by: mickeg on March 15, 2018, 06:08:00 PM
...
The Velocity rims look interesting, does the higher profile make any difference? 
I should have added that if I do this it'll be by SJS, so the choice will be something from what they stock.
As much as the choice of rim, I'm trying to convince myself how much difference a 200g lighter rim will make, one day telling myself it'll make a huge difference, the next that I probably won't notice...
...

Looks like SJS does not sell Velocity rims.  I am not sure what the Velocity company history is, but I thought they were an Australian company.  Thus, I expected the rims to be made there.  But when I bought my Velocity rims I was surprised that they said made in USA on them.  Higher profile, the only thing I noticed was that they take an unusually short spoke because of their shape.  I do not know of any 700c rims that take a shorter spoke with the possible exception of racing wheels.  I wanted a robust rim that could handle touring duties.  I had used Mavic A719 rims before but decided to research other rims first because my A719 wheels were over 10 years old, so I thought that maybe there is something newer and better out there.  A bike mechanic suggested I go with Velocity, he did not specify a specific rim.  I looked at Co-Motion website to see what the Americano uses, they had good things to say about the Dyads.  The Americano is the most robust 700c touring bike I know of, the derailleur version uses 145mm spaced rear hubs because they put tandem wheels on that bike.  So, I took that as a strong endorsement of the Dyad too.  And, I wanted rims that could take tires from about 28 to about 40mm in width.  Thus wanted an inner width in the 18 to 19mm range, and the Dyad was right there.

Lighter rims, when riding I do not notice bike weight that much.  I am more likely to notice weight of the bike when lifting the bike off the ground or when climbing a steep hill.

Some people get excited about rotational weight and say that a heavier rim or tire slows you down.  I am an engineer by training, and I can tell you that it takes work to left a bike and rider from one elevation to another higher elevation.  That amount of work can be easily quantified, it is simply the energy to lift a mass against gravity.  I have done those calculations to estimate how many watts it takes to lift myself and bike up different percent grades and different speeds.  And I can tell you that rotational mass is the same as the mass on the frame for those calculations.  It might feel different, but the amount of work is the same.

On my Titanium bike, the rear wheel with tire (Hutchinson Globetrotter 37mm, 36 Wheelsmith DB-14 spokes, Shimano XT M756A hub, and tube) weigh more than my Titanium frame.  Some would say that is terrible, but it works just fine for me.
Title: Re: Benefits of a lighter rim - Mercury
Post by: martinf on March 15, 2018, 09:24:16 PM
i remember i got the schwalble marathon plus wire bead tyres  in the post i could have cried  :'( :'( they weighed a ton i soon got rid of them weigh matters  for us cyclists  lighter the better  imho.

With Marathon Plus, it's not just the weight. The sidewalls are very stiff, the tread and the layer underneath are very thick. So not as responsive as a similar weight tyre with different construction.

I reckon I am faster with my 26" x 50 mm Nokian studded ice tyres than with the 700C x 28 mm Marathon Plus tyres on one of my visitor bikes. The Nokians are slightly heavier.

The Schwalbe One 700C x 28 mm on my old lightweight derailleur bike are of course faster than both the above.
Title: Re: Benefits of a lighter rim - Mercury
Post by: martinf on March 15, 2018, 09:44:51 PM
I'd be tempted to use a rim that could used with a rim brake, both for the versatility and also as a better match for the front (Grizzly) though I'm open to persuasion.

If you want a match, why not a Grizzly?

Otherwise, I'd suggest Mavic A719, a reasonably light rim but more suitable for your choice of tyres than Mavic Open Pro. 

I have Mavic Open Pro on my old derailleur bike, but they are narrow. Ok for the 28 mm tyres I have, but not the best choice for 32-35 mm tyres.

I chose Mavic 717, similar to the 719 but narrower, for the 26" lightweight wheels on my Raven Sport Tour.
Title: Re: Benefits of a lighter rim - Mercury
Post by: Andre Jute on March 16, 2018, 12:54:59 AM
Sorry, no help at all on the topic of this thread; I'm just making a point to Anto.

i remember i got the schwalble marathon plus wire bead tyres  in the post i could have cried  :'( :'( they weighed a ton i soon got rid of them weigh matters  for us cyclists  lighter the better  imho.

You would have cried harder and longer if you kept them. The Marathon Plus do only two things well: they don't get punctures, and they break your coccyx.

Weight in rotating assemblies has some advantages too, for instance in rolling inertia working both ways (once you get them going they want to keep rolling). But to make that work for a cyclist, first the tyre must offer whatever else is important to him/her/it. My fave Big Apples are heavier than the Plus but the soft sidewalls and lack of tread together with the fat footprint make them both comfortable and securely, efficiently fast, my personal must-have attributes, which nothing else of lesser weight offers. Suddenly I'm not such a weight-weenie!
Title: Re: Benefits of a lighter rim - Mercury
Post by: mickeg on March 16, 2018, 01:35:29 AM
...
I reckon I am faster with my 26" x 50 mm Nokian studded ice tyres than with the 700C x 28 mm Marathon Plus tyres on one of my visitor bikes. The Nokians are slightly heavier.
...

My 26X2.0 (or 559X50) Schwalbe Marathon Winter studded tires are the slowest tires I have ever ridden.  I am glad you found a faster one.
Title: Re: Benefits of a lighter rim - Mercury
Post by: PH on March 16, 2018, 12:40:35 PM

If you want a match, why not a Grizzly?

Ah, two failed Grizzlys are the reason there's a Sputnik on it, the single eyelet construction isn't ideal for a Rohloff and both times i had spokes pulling through the rim. Matching isn't a priority, but to my eye an all black rim without the contrasting brake track stands out. 
I'd forgotten about the Mavic A719, I had them (Or their predecessors) on a touring bike years ago and they were fine, I've added them to the shortlist.
Title: Re: Benefits of a lighter rim - Mercury
Post by: martinf on March 16, 2018, 02:25:13 PM
My 26X2.0 (or 559X50) Schwalbe Marathon Winter studded tires are the slowest tires I have ever ridden.  I am glad you found a faster one.

My Nokians might not be faster than your Schwalbe Marathon Winter - they're just faster than Marathon Plus in 700C x 28. Also faster than the lightweight kevlar bead knobbly off-road tyres I used for ice and snow riding before getting studs. But my Nokians are still noticeably slower than the 26" x 50 mm Supremes or Duremes I generally run on my two Raven Tour bikes.

For me speed and weight aren't an issue with studded tyres - the aim is to arrive at destination without falling off in icy conditions.

The idea of Marathon Plus is to avoid nearly all punctures on a visitor bike where I don't want a visitor faffing around with a hub gear and drum brake. The performance drop doesn't matter too much on a bike mostly used for short trips, but it is very noticeable on test runs of 20-30 kms.
Title: Re: Benefits of a lighter rim - Mercury
Post by: richard s on March 22, 2018, 09:53:59 AM
When I got my Sherpa from Thorn in December 2016 I had lightweight Grizzly rims fitted. Since then I have ridden about 4500k on mainly country lanes in summer and winter weather. that is, some dry roads and some wet and muddy.
I have just had both rims changed to Andra 30 heavier ones as the rear rim had badly worn and actually cracked. My area, North Somerset is hilly, but I don't think I am hard on the brakes, and favour the front brake anyway. I was not very happy with the life of these rims and Thorn did me a deal with the replacement.
Based on my experience I would not recommend lightweight rims for anything other than very gentle cycling.

Richard
Title: Re: Benefits of a lighter rim - Mercury
Post by: Neil Jones on March 22, 2018, 07:09:42 PM
I'm sorry to hear that you've had some issues regarding the Rigida Grizzly rims Richard. I don't know what has been the problem with the more recent stock as I've heard a few people having problems with them, maybe a bad batch or perhaps they've been taken over and quality has gone downhill. I opted for CSS Grizzly's with on my Raven Sport Tour which I bought new in 2011, they've done over 20k miles, still run true and have very little wear on them. I commute in all weathers and live in quite a hilly area. I don't regard them as lightweight in the true sense of the word, to me they are a good compromise.

If I was fortunate enough to own a Mercury I'd be tempted to opt for Mavic Open Pro as Jag's says. Having said that the state of the roads nowadays maybe a slightly more rugged rim may be better.

Neil
Title: Re: Benefits of a lighter rim - Mercury
Post by: jags on March 23, 2018, 02:33:23 PM
Neil on my  Audax i have custom set wheels  open pro rims 105 hubs 36 hole DT Swiss spokes  conti tyres fantastic set hoops could not fault them 8)

hope your keeping well  you seem to be doing a hell of a lot miles fair play to you ,im become a fair weather cyclist. ;D

cheers
Anto.