# Tandem rims



## reamer41 (Mar 26, 2007)

I'm currently running some old (2002-3?) Mavic D521 rims on my ECDM. 
My stoker complains about rear tire squirm. I think I have a 2.4 UST Nevagal at about 34 psi on there now. The squirm has existed with a few different tires. I've tried more pressure but the ride gets harsh.

So these days they hype is for wider rims and I think I believe the hype. The D521 has a 21mm internal width, I believe. I could pick up some MTX33s for a reasonable cost, and I think the ERD is the same, so it would be an easy swap.

What say the other tandem teams, worthwhile swap? Has anyone here made a similar switch and have feedback? The Sun is not really all that wide by evolving wide standards, but wider than what I've got. There is the MTX 39 but it is sooo heavy! Any other suggestions?


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## PMK (Oct 12, 2004)

FWIW, we ran the MTX (most likely 33) on our Fandango. For us they were a great rim with the 2.3 Panaracer tire.

Our ECDM 26 has been rolling Sun Ryhno Lites. With Sun no longer offering this rim, I would up with a mismatched set on a recent rim replacement. I will probably go with MTX on the ECDM.

PK


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## Okayfine (Sep 7, 2010)

We run the MTX33 via the MTBTandems CK wheel set on our ECdM. We run 2.5" WTB Dissents at ~40psi with no squirm and no harshness comments from my stoker. ~360lb team weight.


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## reamer41 (Mar 26, 2007)

Thoughts on lacing new rims got me thinking....

Is there room for 650b wheels and reasonable tires on the back of the ECDM? Has anyone tried it? If money were not an issue I would go buy an ECDM 29, but I can't afford a new frame and fork right now...

(I'm away from home right now so I can't go check frame clearance.)


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## PMK (Oct 12, 2004)

Run the 26 and be done with it. The ECDM 26 is not bad as is and I bet is limited by myself and stoker or often the teams limits.

A well setup 26 is plenty quick.

Each time I want to make a change, the stoker reminds me of what has been done, and with that we both agree if we trained more, it would far surpass the upgrades. Would the upgrades and training combined be even better, maybe, but we don't ride wide open all the time so it probably doesn't matter that much.

Obviously though, I get stupid focused on good suspension...my stoker is naive and has simple voice commands, like "I don't now, but something is not right".

FWIW, a less flexxy wheel will put more to the ground and less effort to corner with higher corner speeds.

PK


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## JokerW (Nov 5, 2004)

"Each time I want to make a change, the stoker reminds me of what has been done, and with that we both agree if we trained more, it would far surpass the upgrades. Would the upgrades and training combined be even better, maybe, but we don't ride wide open all the time so it probably doesn't matter that much."

and I'm willing to bet that pretty much sums up tandem riding with the wife/girlfriend, for most of us.


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## mhopton (Nov 27, 2005)

We ride on a Velocity Blunt 35mm wide rim and run it tubeless at 29psi. I really believe the wider rim does a lot too spread the tire casing and put down a larger footprint. Very pleased overall. 

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## TandemNut (Mar 12, 2004)

Internal width on the original MTX33 is 27.5mm + - . Internal width on the Blunt 35 is 30mm. However, the MTX33 is way stronger than the Blunt 35, but heavier too. For accuracy's sake, the MTX33 I measured is the original 26" welded version. I do not know if the current 26" sleeved version is the same extrusion. The welded version can be set up ghetto tubeless easier than the sleeved version.
I agree that wider rims increase tire performance dramatically. Glad to see wider rims becoming more common.


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## mhopton (Nov 27, 2005)

Alex, when the blunts are done, I'm interested in rebuilding with a set of the 40mm Derby carbon rims. Thoughts? 

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## ki5ka (Dec 17, 2006)

*carbon wheels... *

Carbon and Tandems... made me think of this Carbon Bicycle Wheel EXPLODES at 60kph. - YouTube

Couldn't resist...


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## reamer41 (Mar 26, 2007)

I've got a set of Light-Bicycle carbon rims on my 29er. After bashing them over and thru rock gardens and whatever for 18 months now I van say I would consider putting them on a tandem. 
light-bicycle will do some custom layup. My rims have extra carbon in them and they are strong and stiff. While very affordable for carbon, they're still more $$ than I want to throw at an experiment right now. I say experiment because I would go into it not expecting 5-10 year life from the things. (But compared to the Velocity rims not bad in price at all.)

The thing that amazes me about the carbon hoops on my single-bike: how much stiffer they are than the I-23 WTB rims I took off. The bike tracks SO much better! And I had had no idea my rims/wheels had been flexing until I had the new rims. 

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## TandemNut (Mar 12, 2004)

ki5ka said:


> Carbon and Tandems... made me think of this Carbon Bicycle Wheel EXPLODES at 60kph. - YouTube
> 
> Couldn't resist...


Looks to me like they lost the front tire first. The rim did unwrap itself pretty quickly though.


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## reamer41 (Mar 26, 2007)

TandemNut said:


> Looks to me like they lost the front tire first. The rim did unwrap itself pretty quickly though.


Agreed.
And as racing components they were probably not built for durability.


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## reamer41 (Mar 26, 2007)

mhopton said:


> Alex, when the blunts are done, I'm interested in rebuilding with a set of the 40mm Derby carbon rims. Thoughts?
> 
> Sent from my SCH-I535 using Tapatalk


It would be interesting to see if derby can have a set built with extra material for greater strength. Do the Derbys come in 36 hole?


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## mhopton (Nov 27, 2005)

They do have a 36 hole and they have 2 layup options - regular and heavy duty.

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## XC Mike (Sep 26, 2004)

Has anybody set up a set of Sun MTX33 tubeless using Stan's?


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## mhopton (Nov 27, 2005)

Hey Mike, we run velocity rims vs Sun; however, given the ease of setting non-tubeless rims up tubeless with Stan's yellow tape and fluid, I don't know of any reason why you wouldn't be able to set them up. It's cheap to give it a try.....go for it and see what happens!

FWIW, we run ~31 front, 33 psi rear tubeless. Works great!


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## XC Mike (Sep 26, 2004)

I used Stan's on my Niner EMD a few years ago and loved it...
I did a quick search and it sounded like guys had problems setting up the MTX33 rims??
I just ordered a set of WTB 2.25 Nine Line and they are TCS ready tires so I will call Stan's next week to ask them about the MTX rims.


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