Fat Tandems Builders accommodating 100mm rim w/ 4.8" tire
I'm hoping to gather some intel as to who is actually building fat tandems that accommodate a really big rim/tire combo (100mm rim with 4.8" tire)
What builder is building or plans to build a frame that can accommodate the biggest tire/rim combo available? (100mm rim with 4.8" tires)?
For those that meet the criteria above, what drive train are you running? Cranks?
What forks are you running?
How are the rear hubs working out with tandem loads?
Whatever else is relevant, chime in.
Thanks for your input!
Last edited by ds2199; 12-22-2014 at 01:48 PM.
I think Scott Quiring would be the one to ask about making something that big. When I had our double-Pugs built, I considered using two Moonlanders instead, but heard that the high offset wheel/chainstay makes for a noodle-y ride. What is your team weight? Are you riding in really deep conditions?
Thanks for following up. As far as I can tell, Quiring is the only one making such a tandem at this point.
Originally Posted by deuxdiesel
You asked if I am riding in really deep conditions? I would say that really deep conditions on a tandem are likely not going to work. The added weight makes things harder, but that is why I'd like to have the biggest tire/rim possible. I run a 4.8 on 80mm rims and that is more than I need a lot of the time (but I'm only 155 lbs). I think I could get away with 4.0 tires on my single bike and be fine most of the time.
I'd like to have the best possibility of riding the tandem in snow. The groomed trails or snow-shoe'd trails will likely work best, but we're up for trying to see what we can do.
What I'm trying to avoid is buying a tandem that is limited at an 80mm rim and wishing that I could just try those fatter rims.
In the end, 100mm rims and 5" tires may not be "enough", but I'd sure like to try!
Regarding your double pugs your consideration of the Moonlander, I have actually thought about a double Ice Cream truck.
Actually, a tandem ICT would be great, but by the time you bought two frames ($700-ish each) and the extra tubing and labor to join them, you are looking at close to the same price as a custom Quiring. I went with the Pugs because I already had one, plus a bunch of donor parts, so I only needed to buy one extra frame, which are pretty cheap.
DS, not to derail your topic of 100mm rim width, but FWIW, our local guy running a 29 ECDM has intentions of building a rear wheel with the Russian CF rims.
He seems confident this will fit, but not sure what tire he plans to run. Obviously this will not be for snow, but rather softer sandy conditions which should be similar.
Pretty certain it is this rim, but I could be wrong.
Naran 80 Carbon Fat Bike Rims | Sarma USA
If you want, I can let you know how it fits / works. Not sure what his time frame is to accomplish this. You can even call and ask...Tommy @ The Bicyclery , 561.684.8444.
Reps! We don't need no stickin' reps!
Let me know what they work out. I can't imagine a very large tire can fit inside an ECDM rear triangle, but interested to here the result!
Ventana is building tandems with the clearance for 100mm rims and 4.8" tires. They are building both 170mm rear spacing and 190/197 rear spacing. In my opinion the 190/197 is needed for the big tires or you will have chain rub on the tire on the large rings on the cassette. We have ordered a 197 thru axle version and will be building it as a 1x10 with right side drive so we can use standard fat bike cranks instead of tandem specific cranks. We are planning on running Dillinger 5 studded tires on it but still deciding on whether we can get by with 80-90mm rims or we need to go with 100mm clown shoes. We are on the third generation of single fat bikes and are running 1x10 with 11-40 cassettes and it works fine so it should work fine on the tandem. You just don't need the big gears on fat bikes. Fork choices are limited so I think we will use a rigid fork at this point again due to the fact of the large tires don't need the suspension for the most part. Another unknown is hubs as there are very few choices in the 190/197 spacing and none tandem rated. If you are really planning on running it in snow etc then regular hubs may be fine as the the traction is certainly limited. This will be a winter bike only for us as we have a Ventana ECDM already for summer use. The first batch of frames is supposed to be ready in about 2 weeks
akexress, this is good news!
I had hopes of going the Ventana route, we actually had an order in for a frame, but then there were delays and then they changed to only doing 170/177 spacing, so we decided to wait. Apparently they changed back to also offering "custom" 190/197 spacing, so that is encouraging.
I am very interested to hear how a clownshoe with a 4.8 Dillinger or Lou fit on that 190 frame (if you go with a clownshoe). Please keep me updated on your tandem build either here or offline. I was discouraged from the wider rear spacing when working through my original order, so I am very interested to hear how it all comes together.
I know that hubs are a limiting factor, but as you said, we would plan to ride it primarily on snow as we have another bike for dirt. We had planned on doing 1x with right side drive too. Currently looking at other frame builders as well, more to come on that as I get info.
Last edited by ds2199; 01-07-2015 at 07:18 PM.
I am considering a Ventana build as well. I will likely go 170mm rear as I plan on doing a Rolhoff Speedhub XL. Being that I only have to deal with one cog, I plan on running 80mm rims (looking at the Bontrager Jackalope) with 5" tires. Yes, I know it will not be a true 5" contact patch, but it's close.
RE: Fork. RockShox doesn't have any objections to it's use of the Bluto on the El Gran Jefé, but they do not endorse it. I'll likely go with the I9 hub. So I will give it a shot. This bike will not be enduring hardcore single track, so I suspect it will be up to the duty.
This will be my first tandem build, but my fifth fat build. I've got lots of experience on the fat side, but I none on the tandem side. If you have any feedback, I'd welcome it.
We live Anchorage , Alaska and internal hubs have not done well with the cold. It is not super cold here so a Rolhoff was a initial consideration for us until I started doing some research and the only people whom have had some success are using cleaning fluid in them instead of the normal oil. We started out on singles with 135 offset then went to 170 and now have settled on the 197 thru axle and it really works well. We also started out 3x9 then 2x10 and now 1x10. The popular set up here is a Sram 11-36 converted with a Wolf 40 tooth swap and a 30 tooth chainring. We have been running that on the singles for two years and it works well. I am going to use that same setup on the tandem. We are planning on the the 907 carbon Whiteout fork even though it is not tandem rated it is built robustly. We do not get air on winter bikes and certainly won't on the tandem so I am not expecting problems. Right side drive will be pretty straight forward and have ordered single fat cranks for 190mm spacing. Ventana has there own 100mm eccentric that comes with the frames. I am pretty decided on 90mm Nextie carbon rims as they are only a few dollars more then clown shoes and much lighter. I will probably consider running tubeless. Tandem fat bikes are on the rare side so this is uncharted territory. I was able to discuss at length with Sherwood at Ventana and we are excited to get a frame. We have two of his ECDM tandems and have had great experiences with them and good support. The 190/197 is a custom option with an up charge from Ventana but still a value compared to road tandems. I am thinking 180mm rotors will be adequate for the fat tire tandem for winter use but would want 203 for summer use. Mechanical discs brakes are the way to go in the cold as few people deal with hydraulics on winter bikes and the traction is limited enough you don't need them. Carbon bars will help with cold hands and some nice pogies make it toasty.
Originally Posted by Bacons
Thanks for the feedback. I've scrapped the plan for the Rolhoff as I really want to build a 29+ wheelset for summer use. So I am going to give Shimano's new XTR M9000 line a shot for a 1x11 set-up.
Do you think the Nextie rims are up to the load task? I'm 205lbs., and my stokers will be anywhere from 80lbs. up to 170lbs. So loaded up, total rider weight could reach 400lbs.
Brake suggestions? I've looked at Hope but I've had such great experience with Shimano's XT/XTR on my other rides.
Ventana frame is being ordered this week.
I think the nextie rims should be up to the task . I am going to use the 90 mm wild dragons. I have built a few sets of the Nextie 650b rims and we have put some good miles on them and have been tough. As it will take a while to get them and build them up I will just use a set of rolling daryls that I have built on 907 hubs. I think fat bike rims are inherently strong due to the wide hub flanges and offset spoke holes on the rims especially in 170 or 190 hub spacing. The tires also absorb so much of the shock loading that you almost never hear of wheel failures other then hub issues. As far as brakes in the winter I don't think you need hydraulic as there is just not enough traction to really over stress the brakes however if you plan on running 29r in the summer then yes they might help. We have Hope v2 on both of our mountain tandems and they will stop a truck The only other issue is seal problems in the winter. We have only run mechanical discs on the winter and very few people run hydraulics in the winter here for that reason. Run as large of rotor as you can especially for summer use. I am going to use 180mm avid BB7 for the winter. One other issue is you need a stoker stem that will accommodate a 30.9mm seat post most are too small Control tech does make them in two different adjustable lengths. The 1x11 XTR should be a great choice, what cranks are you planning on using. Word from Ventana today is shipping in about 2 weeks.
Originally Posted by Bacons
Thanks akexpress. GREAT feedback! (and sorry to the OP for hi-jacking your thread).
I will take a look at the 80mm Nextie rim.
I think I will go XTR for brakes. I run them all winter on my El Gordo (and my previous Mukluk) with great success. I do bleed them at the beginning of the Winter season as any bit of air in the lines will cause issues in low temp weather.
Cranksets? I am leaning towards the Race face Turbine (cinch system). My LBS is currently researching this for me.
No worries. It's good to hear what people are doing on their builds and comparing to my own plans. As akexpress noted, tandem fatbikes are rare, and a lot of this is uncharted, so its good to hear all of the details!
Originally Posted by Bacons
I'll be interested to hear how everything comes together after the build and
Have you considered up-grading to Saints?
Originally Posted by Bacons
Good call. A more downhill oriented brake may be ideal for this build. Thanks.
I agree that Hydrualics are better and if you are going to use it year round it will be a better choice. I would then stick to Shimano due to use of mineral oil which does not absorb water so may have less issues in the freezing temps in winter. It will be fun to watch how the fat tandems shakeout here in a few weeks/months.
Update. Frame and fork have been ordered. Updated specs:
Ventana El Gran Jefé (white color), going with the 177x12TA rear
Borealis Echo Carbon fork (150x15TA)
XTR Drivetrain (M9000 1x11)
Shimano Saint Brakes (180mm rear, 203mm front)
Last piece of the puzzle are wheels. I9 hubs are a definite. However, still on fence with rims. I am down to the Bontrager Jakalope or the Whisky carbons. Love to do the Whisky... but it is coming down to cost. The Whisky's are spendy.
Originally Posted by Bacons
Did you talk to Borealis regarding the weight limit on their fork? Do they know it is going on a tandem? I'd guess they would discourage us from using it, but am curious nevertheless. Also, a lot of carbon forks have a size limit on rotor size, did you ask if they have any concerns with a 203 rotor with that fork?
Thanks and keep us posted on the build!
My LBS did chat with them around the fork strength and the use-case (Tandem). They felt is was up to the task. Keep in mind, this bike will not be bombing a rocky mountain downhill at 30mph. This will be a snow and single track trekker.
I do run a Bluto on my El Gordo and I will be interchanging forks. So this will give me some flexibly.
...oh sorry, forgot to address your rotor question. It 'should' be able to accommodate a 203 rotor. However, if not, I am fairly certain running a 180/180 combo would be plenty of power. Stay tuned. More updates as they happen.
I am also considering running a 4.8" tire up front, 4" rear. By the time the build is done, the Schwalbe Jumbo Jims should be available.
I have a set of 90 mm Wild dragon carbon rims by Nextie on the way and will be using Hope Fatsno hubs in 197/135. I am also using a single bike fat fork. I know the owners of 907 well and they are quite confident that their carbon whiteout fork is up to the tandem task. We already have two of them on singles and they are robust. I will go with as big of rotors will fit and and for sure a 203 will fit on the fork the frame is an unknown at this point. Dillinger 5 studded running tubeless for tires. 1x10 with oneup 40t conversion on race face cranks. Unfortunately I heard from Ventana that the frames are going to be a bit late as one of their welders was out sick last week. Will post pics of build as it progresses.
AK and other's with tandem crank experience. The BB will be 100mm front and back. Since I will be running a 1x11 set-up, would you do left or right side timing? Do you see any issues with Race Face (and if so, other crank recommendations)? Thanks!
I think right side timing with 1x is a no-brainer. My plans are to use the RF Cinch cranks Front & Rear.
I have experimented with 2x with right side timing chain and it requires perfect front deraileur adjustment and even then, I've seen occasional issues.
I do not recommend right side with 2x. (my .02 cents)
Standard RF rings or would you go narrow-wide?
My plan as of now is RF Turbine w/ cinch.
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