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Afternoon project: BIG FAT DUMMY!!!

39K views 51 replies 19 participants last post by  2:01 
#1 ·
I decided to see how simple/involved it would be to run 26"x3.0" Duro Razorback downhill tires with freshly-built 65mm wide Surly Large Marge rims on my Big Dummy. Wow, many hours, and a busted thumb, thanks to one bad swing with a hammer.

Image #1: how lame does the stock 2" wide Schwalbe Big Apple look mounted onto a 65mm wide Large Marge rim?


Image #2: 26"x3.0" Duro Razorback tire mounted on Large Marge rim (looks more appropriate)


Image #3: I cut the front cantilever bosses from the fork, and test fit the Razorback mounted to the Large Marge rim. No clearance problems whatsoever!!! :thumbsup:


Image #4: another angle of the front fitment


Image #5: now the "fun" :rolleyes: part, shoehorning that fatass tire/rim combo in the back, there is only 5/16" of room between the tire and the bottom bolt hole (I had to remove the bolt for the tire to fit)


Image #6: I know, I know, the paint colour doesn't match 100%, but it's such a small area, and I was in a hurry, you know


Image #7: have hammer, will whack-less than 3/32" space here, should be interesting at times when riding


Image #8: holy crap that thing is HUGE!!!


Image #9: crapola, it was getting dark and late, I will have to finish up tomorrow, but the good news is that several test rides have confirmed that this actually works without any major issues… other than not being able to use the two largest cogs on the cassette but I figured that out before going the fat route


I have a bunch of cool iron-on patches I want to put on my FreeRadical bags before I put them back on the Freeloaders, hopefully I will be able to tackle that part first thing tomorrow morning. :skep:
 
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#25 ·
he he he..

My 1fg (26er) just got swapped with a 1fg (29er) and I have this stans kit and mutano 2.4s sitting around.

And the thought that crossed my mind was "ya'know, in the spring I think I'll put the mutanos on the dummy and ride it off road..."

And like Devo, the dummy is rolling on the speedisc xls too...

:D

Like minds and all that...

g
 
#27 ·
SelfPropelledDevo said:
when you see something like this: http://forums.mtbr.com/showthread.php?t=674189

how can you not want a fat tired cargo bike

obviously thats a tandem, but you get the gist
Leave it to the Belgian!!! (I am currently enjoying a 750ml bottle of Affligem Triplel!!!) :cheers: (hopes there's an emoticon for that one!)
 
#28 ·
Image #2: 26"x3.0" Duro Razorback tire mounted on Large Marge rim (looks more appropriate)
Glad I found this. I ordered parts earlier this week to do the same project. Your pictures aren't working, so I can't see if this bike had a derailleur. If so, I assume the Razorback prevented you from getting to some of your rear cogs. How many did you lose access to b/c of the tire width?

To get into the nearest "big" town me and the kids have to ride a very steep, loose path for about a mile before we hit a rails to trails. I have BA's on my Dummy right now and we don't have enough traction plus I'm getting some complaints from the passengers about bumpiness. I'm hoping the Razorbacks will solve both problems.
 
#29 ·
Sorry, I used to host my images on my then-reliable .mac service account, but they end of lifed an otherwise useful service. I still need to find an image hosting service. Yes, running a rear derailleur. Zero clearance issues on a 2x9 drivetrain setup. I’ve since changed the tires to 2.5" Maxxis Hookworms since the bike sees fewer trail rides and more paved surface rides.
 
#30 ·
Sorry, I used to host my images on my then-reliable .mac service account, but they end of lifed an otherwise useful service. I still need to find an image hosting service. Yes, running a rear derailleur. Zero clearance issues on a 2x9 drivetrain setup. I've since changed the tires to 2.5" Maxxis Hookworms since the bike sees fewer trail rides and more paved surface rides.
Are you running a true double? I have a 22-32-guard on a triple and I was rubbing in my lowest gear w/ 2.35 BA's (haven't taken calipers out to do a true width measurement). I had to space out my bb 2mm to the drive side to fix this.
 
#31 ·
Well, that was underwhelming.

I received the Razorbacks yesterday. The good is that I like the tread pattern a lot and I think it will work well for my intended use.

But the main reason to drop to 24" was to get more volume. My Big Apples (26x2.35) measure 58mm in real life. I don't expect tires to correspond exactly to the stated width, but I expect them to be close. The Razorbacks (stated width 3.00") measure 65mm in real life. I'm using a 39mm rim (Alex DX32).

I dont' think I could have used a larger 26" tire on the rear of my bike, so building the 24" wheelset wasn't a total waste. But I was certainly expecting to gain more than 7mm tire width.

I chose the Razorback over the Felt Berm Master 24x3.00 because of the tread pattern. The Razorback will certainly do better in mud and slop, but I'm going to try to find out what the real measurement is on the Berm Master and try those out if they get me more volume. The 24" tires are more about giving my kids a smooth ride on bumpy paths than anything. I'll try try to post some pics as time allows.
 
#40 ·
Moose,

Do you know the trail measurement on your bike? Would you mind asking the builder if you don't know?

Putting the 24" wheelset improved the handling my lowering the trail. Especially when climbing something steep it is much easier to keep the front end tracking straight with reduced trail. This is even more pronounced on bikes with a front rack. Ideally, if the builder knows the bike is going to have a front rack either the head tube angle should be steeper or fork rake should be increased (either change reduces geometric trail).
 
#52 ·
Just bumping this up. I'm having thoughts of going fat(ter) on my Big Dummy. Leopold - Your pictures don't show up. Mind putting them back up? I'd like to see what the clearance is like. Some 26x3 Knards or DW's would be pretty cool back there. Would offer my kid some cush as well.
 
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