# retrofitting a 1992 Santana Rio



## rockman (Jun 18, 2004)

Hi all, my first post in the tandem forum occurs because I have cleaned the mothballs off of my old tandem to ride with my 9 year old daughter, offroad and to school. My wife and I used to ride it a bunch back in the early 90s but then it gradually became inactive as we got more and more into our own bikes. Anyway, it's in decent working order but it's got cantilever brakes, cheapo wheels, and a rigid fork. I'm 30 pounds heavier than the old days and the flat bar setup isn't cutting it. We've been riding it on some of the easier singletrack here in Flagstaff, Ariz and my daughter is having fun with it so I see it as a great way for us to share some quality time while still getting in more of a workout for me rather than riding our own bikes.

At the very least I'll put on a thudbuster seatpost for her. Even though it's a 7 speed I can upgrade that later. The big question is whether or not it's worth the effort to install a suspension fork and whether or not this will noticeably affect geometry and handling? It's got a 1 1/4" headset so I guess I would need a CK Devolution headset so I could put on a decent 3 or 4" travel 1 1/8 steertube fork and also give me the option of a riser bar. Are there other options besides a costly King headset? Any recommendations on a good tandem fork? Possibly a thru-axel for a nice stiff front end such as a RS Revelation w/ a maxle? Of course that would mean a new wheel but then I could put on a F. disc brake and maybe upgrade the rear to v-brakes rather than brazing on disc brake tabs. Any ideas welcomed:thumbsup: Thanks!


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## Speedub.Nate (Dec 31, 2003)

If you don't want to spring for the devolution, check out Problem Solvers headset reducers. They should be available through all the usual suspects, and are in the $25 price range. Those plus a decent dirt jump rated headset (FSA Pig Pro) ought to still save some coin over a King.

Ya know, Alex at MTBTandems.com has an 80mm '06 Manitou on his "garage sale" page that might work out on that bike. You don't list your current A-C height or head angle, and the AC isn't listed for the Manitou fork, but I'd guess you'd want to stick to the shortest travel possible to prevent the steering from getting too floppy.

BTW, it has a 20mm axle.

I think you're right on track with your brake and seatpost considerations. In fact, I'm just switching a Thud ST off another bike over to the captain's position on ours, but won't get to assess it for a few weeks more. My wife swears by the standard travel Thudbuster, though your daughter may need the special order lightweight elastomers.


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## rockman (Jun 18, 2004)

Thanks for the reply. 

I don't have the old specs but the head angle looks pretty steep, at least 71 maybe even 72 degrees. A-C ht is about 380mm and the headtube is pretty short at 3.0 inches. Oop, mixed my units. Even a 3" fork would soak up some of the rough stuff and at least allow me to run a 2.4" tire rather than the current max of 2.1" Ah, the good ole days. We thought that was wide.


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## Speedub.Nate (Dec 31, 2003)

rockman said:


> Thanks for the reply.
> 
> I don't have the old specs but the head angle looks pretty steep, at least 71 maybe even 72 degrees. A-C ht is about 380mm and the headtube is pretty short at 3.0 inches. Oop, mixed my units. Even a 3" fork would soak up some of the rough stuff and at least allow me to run a 2.4" tire rather than the current max of 2.1" Ah, the good ole days. We thought that was wide.


Hmmm... I dug around and found some references to the 80mm Manitou and a 455 A-C height, less 16mm for sag. On a solo bike with a normal wheel base, that would result in a nearly 3° slackening of the head tube.

With a long tandem wheelbase, the impact would be a little less. I ran some numbers, and am coming up with a 1.5° HTA change, assuming a wheelbase of 73" and a starting HTA of 72°.

I don't trust the answer completely because I plugged the numbers in to a calculator and not a spreadsheet, but at face value, it sounds reasonable.


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## rockman (Jun 18, 2004)

That sounds reasonable. I think I could get used to a little more slack HA but not too much. Tandems are hard enough to steer on trails as it is. 

Does an 80mm fork limit you to a 6" rotor? I would think you would want bigger than that on the front.


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## patineto (Oct 28, 2005)

you can always use one of this, no changes in geometry, no lost of handling or rigidity.









Hydrolic damper and everything.


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## Speedub.Nate (Dec 31, 2003)

rockman said:


> Does an 80mm fork limit you to a 6" rotor? I would think you would want bigger than that on the front.


I see 210mm max listed for the 2008. Don't know what it is for the '06.


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## TandemNut (Mar 12, 2004)

I think all of the jumping/dh forks are rated for 8" rotors.


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## rockman (Jun 18, 2004)

Ok, so I'm gonna go with a Zoke thru axel Dirt Jumper and lace up a new wheel. I can get a good deal on Hope or a Phil Wood thru-axel hubs. Would a SunRingle Rhyno Lite 36h rim be strong enough for a front wheel? I could also go DT Swiss 5.1D or WTB laserdisc-FR. I'm not sure if these hubs are tandem rated either but with a combined stoker/captain weight of less than 300 pounds they should be ok? I could go with a Hadley as well but that's more cash. 

As always, thanks for any input


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## rockman (Jun 18, 2004)

From perusing the P. Wood website it appears that the 36h thru-axel front hub is tandem rated. And from checking out the excellent MTBtandem site the sun ringle rim will handle the load just fine so I think that's what I'll go with.


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