cellery

Hi guys, I recently restored this long neglected 1979 Univega Sportour into a quite rideable and fun cross bike. so far I've only ridden it on unpaved canal paths in the city. It's got 27 inch rims so I put some great 27in x 35mm Cross-Terra tires on and converted the old 5 speed downtubes into a 7-speed indexed brifter setup (thank goodness for the new Shimano Tourney line bringing ancient bikes into modern times!). I'm what I'd consider a serious road cyclist for many years, but I got the gravel bug and have some concerns about the brakes and questions about gearing.

How do rim brakes hold up on extended gravel travels? I'm well aware of the diminished stopping power of rim brakes in wet/muddy conditions. While dirt roads here in southern Arizona are dry most of the year, there is always the off chance of getting into some mud in the monsoon season; the tight clearances of rim brakes also concern me when it comes to getting rocks and dirt clods gunked up into the wheel. Am I just imagining these concerns or are rim brakes adequate for gravel grinding and light duty gravel touring?

2nd, I'm thinking about switching out the old 52x42 road chainrings for something more appropriate in the cross range of 46x34. Because the old Campy crank uses an outdated 18mm BCD. I can't just go out and buy new chainrings so the whole thing has to be replaced. It seems like cranks specifically marketed to cross bikes are rather expensive, $150+ and I don't want to spend so much to upgrade a very old bike. What is the possibility of taking a shimano mtb triple and converting it to a double? If I have a shimano double road shifter/derailleur right now, will it work as is to take the granny ring off a mtb triple and just set the limit stop at the middle ring - or will there be an issue with mismatched indexing and/or inadequate derailleur throw? Thanks!

fietsbob

Horses for courses , talk about the terrain where you will be riding the bike , shown..

the brake hold up as well as the rider pays attention to the regular service on the whole bike , in General..

its not about the parts its about the upkeep .

lose the big ring and front shifter , and run a 1 by and its one less thing to fix.

gravel grinders seem a summer thing .. and You are in Arizona.. a place not renowned for Washington-Oregon coastal weather ,
thats why so many from here are there in the winter.

Cyclocross racing is a fall winter sport , then You might as well get a competition bike for that sport

probably wont need a mud tire for that either .

need a low gear , how about a tripleizer 42t , and a longer BB then the granny bolts to the new 42 t with a second, smaller bolt circle.


by the way any 110 BCD crank will take a 34t chainring , some are quite Cheap ..

the archives are full of past answers to the same sort of question do some more reading , though it is work .

cellery

I'm not interested in cross racing. Single speed - been there done that and decided I wanted a wide range; this was a project bike that lent itself well to being a gravel beater so I intend to ride mixed paved/dirt road of varying conditions - definitely not singletrack and definitely not soft sand, or else I would be going xc mtb. I want to keep the existing 2 speed shifter because it was a recent purchase and again I don't want to be dumping tons of money into it; so a triple is not for me. I guess I could go the cheap crank route and put some cheap rings on rather than buying the whole combo as you suggested. Good to know the rim brakes will be good for the long haul in those conditions; I don't skimp on upkeep.

bikemig 

You can pick up a compact with a square taper BB and your total costs will be under $100: FSA Vero Crankset - Outside Outfitters

Or pick up a really cheap square taper triple: Shimano Acera M361 Triple Chainset Square Taper | Chain Reaction Cycles

I'm doing a build like this on a vintage mtb and running bar end shifters; cheap brifters will work even better though for a gravel grinder.

fietsbob

Cheap;: origin 8 cranks Product Description | Origin8

And 2 chainrings , you pick the sizes https://www.origin8.bike/product-desc..._model_uid=703.

and a BB of appropriate length LBS can supply al 3

Origin 8 is a brand of J&B imports .. seems Amazon is one of their clients ,

but amazon wont help you pick the right BB length and its just a crapshoot with out it being in front of Me.

Dorf411

Pic 3, seatpost is installed backwards it could make your seat position awkward. Otherwise the bike looks cool and I think you probably could benefit from a crankset with smaller rings. I have always liked a large ring of 46 or 48 especially for my commuting bike and have typically run a large of 50 on my road bike.

Kopsis

Cantilever brakes are rim brakes and they've been working fine for cyclocrossers for decades. Road calipers do have mud clearance issues, but honestly how much gravel riding are you going to do during a monsoon? As for kicking up debris -- I was in a CX race once when my front tire grabbed a stick and jammed it between the tire and the fork. Didn't make any difference that I was running super wide cantis with tons of clearance Ride it as is and see how it goes (it's not like you can switch to cantis or disks anyway). I think you'll be fine.

cellery

I'm aware it's installed backwards - I've been playing with my seat aft/forward adjustment when the pic was taken.

Agree, putting new stuff on old bikes sight unseen is an issue; I'll probably go LBS for a new BB. The Origin 8 looks good pricewise. Thanks guys for the ideas!

BluesDawg

I wouldn't worry about the brakes. Tire width limitations would be the biggest potential drawback in dry conditions, but it appears you are doing OK in that regard.
Depending on the hilliness of your rides, a compact road crank and wide range cassette (depending on rear derailleur capacity) could be a big improvement. With a mountain triple, you may have front derailleur reach problems and the wider chainline and Q-factor could be issues. Nice job so far. Keep us updated.

Barrettscv 

Great job so far on the bike. The Velo Orange 46 & 30 crankset for $89: VO Polyvalent Crankset - Cranksets - Components

cellery

Thanks! This piece is exactly what I was looking for; none of that messing with converting a mtb triple, etc. It's already got a mega-range freewheel so this should make it perfect. If I decide to buy this I'll post some ride time pics post-install, maybe even with the seatpost installed correctly.

cellery

I uncovered these issues as well when researching parts. But this should not be a problem with the VO crankset that Barrettscv suggested, correct? It appears to be designed with road parts in mind. Sorry, my knowledge of crank/derailleur/frame compatibility is limited.

Barrettscv 

Yes, the VO Crankset is a JIS Square taper and will fit your bike easily. Velo Orange recommends a 118mm wide Bottom Bracket. Chances are that your existing bottom bracket will be a JIS Square Taper in the 112 to 118mm range and will work.

Removing these cranks involve a crank-puller. Any bike shop will have this tool.

unterhausen

I used a compact crank and some tektro long reach brakes to turn my old touring bike into a gravel bike. Other than the fact that I would like bigger tires, I was perfectly happy with it as a gravel bike

fietsbob

if desiring less .. there are zero setback seat posts to get, too ..

then the look wont be backwards appearing ..

real forward seats were in Tri Bike setups .. It's been done..