Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-13-07, 07:43 PM   #1
wroomwroomoops
Sir Fallalot
Thread Starter
 
wroomwroomoops's Avatar
 
Join Date: Jul 2006
Location: Helsinki, Finland
Bikes:
Posts: 5,275
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
How would/does a Nexus 8 fare on a tandem?

If I built a rear wheel with a Shimano Nexus 8 gear hub, could I expect it to last, on a tandem, or is it too sensitive?

I'm asking because I just happened to have one laying around, and I want to replace the front+rear derailleur setup on a tandem.

The Nexus 8 has a rollerbrake.

Maybe I should ask this in the mechanics' forum?
wroomwroomoops is offline   Reply With Quote
Old 07-13-07, 08:33 PM   #2
TandemGeek
hors category
 
TandemGeek's Avatar
 
Join Date: Jan 2002
Bikes:
Posts: 7,208
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'm not positive, but as best as I can recall I believe the Nexus hubs have max RIDER weight limitations that fall somewhere between 190lbs - 250lbs (a quick check yielded a range of weights for the 3, 7 & 8 speed models). I'm not sure if the weight limitation pertains to the hub brakes or the hub itself.

Edit: Added "Rider" to answer next question.

Last edited by TandemGeek; 07-14-07 at 06:45 AM.
TandemGeek is offline   Reply With Quote
Old 07-14-07, 02:09 AM   #3
wroomwroomoops
Sir Fallalot
Thread Starter
 
wroomwroomoops's Avatar
 
Join Date: Jul 2006
Location: Helsinki, Finland
Bikes:
Posts: 5,275
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by TandemGeek
I'm not positive, but as best as I can recall I believe the Nexus hubs have max weight limitations that fall somewhere between 190lbs - 250lbs (a quick check yielded a range of weights for the 3, 7 & 8 speed models). I'm not sure if the weight limitation pertains to the hub brakes or the hub itself.
What does that weight limitation even mean? And this is a general question, even with tires: say a tire has a weight limit of 110 Kg. Is that the weight of the rider? The weight on a single tire? Total weight of bike + rider?


EDIT: if the weight limit pertains to the brake, then the "weight" thing is clear: it's about the total weight of bike+rider(s).
wroomwroomoops is offline   Reply With Quote
Old 07-14-07, 07:29 AM   #4
TandemGeek
hors category
 
TandemGeek's Avatar
 
Join Date: Jan 2002
Bikes:
Posts: 7,208
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The the only hard and fast reference I could find in about 5 minutes pertains to the Inter-M roller brake. It's not so much a limit as it is a warning that the brake was only designed to meet a specification for a total weight of 100kg, after which the brake may not perform as designed (extract below). It would probably be a good idea to contact Shimano's tech support folks and ask them flat out: Is there a max torque / weight limit on the Nexus 8?

Like the Rohloff, the constraints seem to be spoke count and drop-out spacing. The Redline uses improved bearings designed to support off-road use of the hub so that's a plus. The drop-out spacing is something of a "tweener" in that at 132.5mm it falls 1/2 way between the road spec of 130mm and off-road spec of 135mm to seemingly fit both. Trying to put one on a tandem with 145mm spacing would obviously be something that would require technical direction/advise from Shimano. The 36h spoke count isn't as big of a concern because the hub's flanges are tall enough to yield a wheel that's probably as strong as any 40h tandem wheel.

Here's a link to a fairly detailed review of the Nexus 8 Redline used on a single bike: http://forums.mtbr.com/showpost.php?...3&postcount=78

As for weight limits in general, I can't recall seeing any bicycle tires with weight limits, but with respect to rims and wheelsets the often times cited limits of 180lbs - 200lbs always assume a bicycle with two wheels and tied the weight to the rider. This may vary from manufacturer to manufacturer but they usually specify, such as American Classic does in their tables: http://www.amclassic.com/pdfs/WheelWeights.pdf
Attached Images
File Type: jpg Inter-M brake.jpg (59.5 KB, 14 views)

Last edited by TandemGeek; 07-14-07 at 11:05 AM.
TandemGeek is offline   Reply With Quote
Old 07-14-07, 11:28 PM   #5
wroomwroomoops
Sir Fallalot
Thread Starter
 
wroomwroomoops's Avatar
 
Join Date: Jul 2006
Location: Helsinki, Finland
Bikes:
Posts: 5,275
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by TandemGeek
The 36h spoke count isn't as big of a concern because the hub's flanges are tall enough to yield a wheel that's probably as strong as any 40h tandem wheel.
I thought the exact same thing! Thanks for helping me make up my mind... about this detail of the implementation.

Quote:
Originally Posted by TandemGeek
Here's a link to a fairly detailed review of the Nexus 8 Redline used on a single bike: http://forums.mtbr.com/showpost.php?...3&postcount=78
Sadly, I don't have the redline version of it. Now, I'm thinking of canning the whole project.

Quote:
Originally Posted by TandemGeek
As for weight limits in general, I can't recall seeing any bicycle tires with weight limits, but with respect to rims and wheelsets the often times cited limits of 180lbs - 200lbs always assume a bicycle with two wheels and tied the weight to the rider. This may vary from manufacturer to manufacturer but they usually specify, such as American Classic does in their tables: http://www.amclassic.com/pdfs/WheelWeights.pdf
It's written in all manu catalogues I've seen so far - and never seen it defined. So, what you're saying is, they don't mean the weight on one tire, but the weight of the rider when both tires are that tire.
wroomwroomoops is offline   Reply With Quote
Old 07-16-07, 04:59 AM   #6
mrfish
Senior Member
 
Join Date: Dec 2005
Location: London, UK
Bikes: Trek T200 plus enough others to fill a large shed
Posts: 562
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If you fancy trying one for rides round the park and gentle road trips I would just go for it, since this sort of riding isn't going to stress it as highly as a fit MTBer giving it grief. However the application would be experimental and if you're heading far from home say doing a touring trip, it's probably worth ponying up for a Rohloff.
mrfish is offline   Reply With Quote
Old 07-16-07, 06:02 AM   #7
wroomwroomoops
Sir Fallalot
Thread Starter
 
wroomwroomoops's Avatar
 
Join Date: Jul 2006
Location: Helsinki, Finland
Bikes:
Posts: 5,275
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Okay, I know the Rohloff Speedhub is teh bestest, but I just don't have the money for it.

Is there any other hub gear, apart from Rohloff, that is sturdy? I don't need the huge span in gear ratios that the Rohloff offers. Heck, not even the 300%+change of the Nexus 8 is necessary. I just need it to be strong, and cheap. I also have a wheel with a SRAM S7. How does that fare, in the robustness department?
wroomwroomoops is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 01:02 AM.