Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
10/27/22 7:17 p.m.

I've had this Brisa probably about 14 years, but I haven't ridden it much at all in the last 6.
 

Now that I've been spending a lot of time on my full-suspension MTB I'd like to start working on getting back my trials skills. Unfortunately there aren't any good local spots for urban trials, which means a bunch of riding around town - and this bike really sucks for that. 

 

There's a few ideas I have in mind. First I want to get a dropper post with external cable routing. It's a 27.2 seat tube, so that's convenient. Unfortunately it's pretty mauled up inside so it's a bit of work to slide the seat up/down with the quick release. 

Next I'd like a shorter stem & wider bars. I've never really liked the longer stems that traditional trials bikes typically have. That should be a cheap & easy upgrade. 

 

Lastly I'm tired of single-speed & want to install some gears on it. It's a 135mm hub, so I think an 8-speed cassette will be plenty. But here's my 2 questions:

  1. Since I have the bash ring on the cranks I need to replace the small chainring with something larger. I've not yet measured the BCD yet, but I'm hoping I can find something bigger than the current 21t ring?
  2. Is it possible to use a 1x12 clutch type derailure with an 8-speed cassette & shifter? It seems like it should work, but I can't find a definitive answer online. 
     

adam525i
adam525i GRM+ Memberand Dork
10/27/22 10:23 p.m.

Once you go beyond 9 speed the pull ratio's start to change on rear derailleurs so a 1 x 12 probably won't well unless you use a friction shifter. I'd look at the Box 9 9 speed group as an option which will work fine on a standard freehub body.

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
10/28/22 5:59 p.m.

In reply to adam525i :

Cool, thanks!

Well it's been a while, but I finally made a bit of progress. 
 


 

I'd picked up a Crank Bros. dropper post at the local shop's Black Friday sale, but even after modifying it I still couldn't get it low enough in it's dropped position. So I ordered a cheap seat post off Amazon, but didn't consider that I couldn't slide the seat far enough forward to compensate for the seat tube angle. So I ordered another cheap seat post that did allow me to slide the seat all the way forward, and finally the riding position is bearable.

Work gave us a $150 Amazon gift card, so I picked up some wider bars(that I still had to cut down) & a shorter stem. Swmbo bought me a Shimano 8spd cassette & shifter, and I got a chain this weekend for it. 

I had 22-16 gearing, which is good for trials, but to low for riding around town from spot to spot. This cassette has a 16t plus 2 higher gears & feels like it'll work better. 

I have no use for the 2 lowest gears though, so I cut the chain a bit shorter to help with chain slap & just installed a longer stop screw in the derailure to prevent me from accidentally trying to drop into those gears. 

Depending on how this works out I may get a new lighter rear wheel built, with a narrower rim & hub with more engagement points. If so I'll also get a pair of matching tires, possibly Maxxis Ikons like I have on my MTB. 

mikeonabikesmith
mikeonabikesmith New Reader
1/12/23 7:05 p.m.

I wanted one of these in the worst way back in the day, great to see one still being ridden. Not sure what they go for now but I always thought a hammerschmidt 2 speed crankset would be a good solution for the problem your describing getting to and from spots. Engagement and weight being the downside. 
I'd expect you can pick up a second hand wheel pretty cheap for that, 135 spacing is all but dead. The dx32 hoops were pretty good back on the day, don't see any reason to get something more narrow? 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
1/12/23 8:04 p.m.

In reply to mikeonabikesmith :

Thanks!

Modern MTB rims seems to be plenty strong while being much lighter. I'll also be getting new tires, so that'll save some weight too. The current wheel/tire combo is heavier than I'd like, plus I really want a hub with more engagement points than this Hope has. 

Do you have any idea how old this frame is? My best guess is late-90's, but I've not found any info about them online. 

mikeonabikesmith
mikeonabikesmith New Reader
1/13/23 10:41 a.m.

In reply to Pete Gossett (Forum Supporter) :

That's fair re: weight and engagement. I'd encourage you to keep as wide a rim as you can, though, mostly to keep the tire profile happy. Looks like you might be running tar on the front rim? An angle grinder to the rim does wonders for braking power...

I think you're correct on the vintage. Brisa made the b26 through the mid(?) 2000s but the decals and color schemes were a bit different. I'd guess yours is late 90s or maybe very early 2000s. I don't think there were any geometry changes, but brake post updates and braces and little bits were updated if I recall correctly 

 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
1/13/23 6:08 p.m.

In reply to mikeonabikesmith :

Thanks for the info/history. No tar, it's just what's left of the anodizing on the front rim. It's a cheap non-name one that I grabbed off some junk bike I had at the time. 

I'm running brake pads from a place I found when I built the bike 12-13 years ago. It was something like TrialsPads.com? They're still super sticky after all these years!

I was talking to the local bike shop owner & it sounds like the city has a place we can setup some obstacles under an overpass. He had some pallets sitting out by the street at the shop, so I loaded them in the van this morning. 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
2/12/23 7:53 p.m.

Well I've been doing a E36 M3ty job updating this thread.

Running on the inner chain ring was too low for the cassette, so I had to figure out my options. I tried installing a 28t chainring on the big side, but it was too large & hit the chainstay. Looking around I decided to try the cranks off my old MTB, and fortunately the offset was just different enough to (mostly) clear the chainstay - I just needed to do some slight clearancing. The other bonus is I now have 175mm crank arms instead of the previous 180mm that were on it. 
 

 

I took it for a ~7 mile ride today & the gearing works great. I only jumped a couple curbs, went up & down a foot high ledge, and hopped up a short flight of stairs. It's going to take some work to get my trials skills back, but at least I have the means to work on them now. 
 

My next step is probably to replace both tires. I like the Kenda K-rad on the front, so I'm thinking I'll order a pair of them in 26x2.5. They should fit, and allow me to run a bit lower pressure without increasing rolling resistance too much. Eventually if I can get some skills back I'll probably spend some $$ for a better rear hub with more engagement points, but for now it's not holding me back - that would be my lungs, legs & arms. 

mikeonabikesmith
mikeonabikesmith New Reader
2/19/23 8:40 a.m.

Not sure what gen hub you have, but I remember folks modifying them back when I was riding trials more. Might be feasible to grind down 2 pawls so 2 engage at any given time vs 4 - doubles the POE. I don't recall this being a durability issue as much as it was an increased drag thing? Which doesn't matter in a trials application. Ali Clarkson has a good video on this

https://www.youtube.com/watch?v=0Mc1kBtz2PQ&t=20s

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
2/19/23 10:21 a.m.

In reply to mikeonabikesmith :

I pulled it apart to check, but unfortunately my hub only has 2 pawls. 

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