Convert a road frame to a hybrid disc frame?

[john92]

I’m relatively new to the forum, but have something in mind that I don’t see a lot of people discuss about. Yes, disc bikes are the big debating topic here, whether its to get a new disc bike or not, what’s the difference in weight, do you actually go faster, or do we live in areas where disc brakes are needed? etc...

There’s this crazy idea that why not convert the current rim brake bike to a hybrid disc frame by changing out the forks with a disc fork and buy new front shifters and front brake kit (perhaps front wheel too) for the build? What will end up is a ultimate hybrid that allows 80-90% of the disc performance braking in all weather and even a lighter frame compare to full disc? It seems to be reasonable for having a stronger front brake since road bike incorporates 160mm/140mm front n back, as well as race cars on the street putting bigger ceramic brakes in the front only.

Yes there could be three factors to turn people down: The look? (Not for perfectionists), the hood lever urgonomics? (Ultegra and dura ace group sets actually have very identical hood levers between disc and rim brakes, not sram nor campy). And yes there’s the cost... I assume people who use higher end group sets or have nice rim bikes won’t bother to just get a second bike in full disc bike/frame to build...

What are all your thoughts and experiences on this?

[mattr]

It's been done LOADS in the MTB and more recently CX world. It works well.

Don't even need new shifters, just get a BB7 Road caliper to run on your new fork and wheel.

[ooo]

I have tested it on a few bikes and I can confirm that rear disc is rarely needed

1) flat bar gear hub + front hydro disc + cable rear rim brake
2) drop bar di2 mech + front mechanical disc (trp spyre) + rear rim brake
3) drop bar di2 hydro + front disc + rear disc

n1 - best for commuting, including winter with studded tires, rear have very slow wear
n2 - best for loaded touring, and it can be simply converted dropbar/flatbar at any moment
n3 - best for racing (I can tell difference disc hydro+hydro > disc mechanical+mechanical)

Ultegra di2 shifter can be used almost with any cable brakes, including
v-brake (linear pull) for rear, mtb mechanical disc (linear pull bb7 mtb) for rear and sometimes front
trp spyre disc with shimano road pull ("middle pull" between linear mtb pull/road short pull) for front/rear

n2 and n3 use same left and right shifters
if you want drop bar + hydro disc + cable brake you need to use different shifters:
It looks like mechanical shifters ST-r8020 and ST-r8000 are too different,
but di2 shifters ST-r8050 and ST-r8070 looks more similar and you can try to pair them

[john92]

I have tested it on a few bikes and I can confirm that rear disc is rarely needed

1) flat bar gear hub + front hydro disc + cable rear rim brake
2) drop bar di2 mech + front mechanical disc (trp spyre) + rear rim brake
3) drop bar di2 hydro + front disc + rear disc

n1 - best for commuting, including winter with studded tires, rear have very slow wear
n2 - best for loaded touring, and it can be simply converted dropbar/flatbar at any moment
n3 - best for racing (I can tell difference disc hydro+hydro > disc mechanical+mechanical)

Ultegra di2 shifter can be used almost with any cable brakes, including
v-brake (linear pull) for rear, mtb mechanical disc (linear pull bb7 mtb) for rear and sometimes front
trp spyre disc with shimano road pull ("middle pull" between linear mtb pull/road short pull) for front/rear

n2 and n3 use same left and right shifters
if you want drop bar + hydro disc + cable brake you need to use different shifters:
It looks like mechanical shifters ST-r8020 and ST-r8000 are too different,
but di2 shifters ST-r8050 and ST-r8070 looks more similar and you can try to pair them

Sounds like a good solution, cool to see that there are actually people doing it. I was thinking all about hydro braking front that’s why I mentioned ergonomics on hoods.

[john92]

It's been done LOADS in the MTB and more recently CX world. It works well.

Don't even need new shifters, just get a BB7 Road caliper to run on your new fork and wheel.

Yeah I noticed, just that there aren’t many conversions or discussions happening in the road category and I was interested in why and what’s holding back for people to do so. Industries are pushing towards buying full disc frame/bike like all other categories, but other categories seems to find this solution a lot earlier than road.

[Zakalwe]

Harder to convince people they need to buy a new frame and wheel set if they know the only need a fork and one wheel

[ooo]

if you already have R8050 bike you have to upgrade 1 lever to ST-R8070-R (177€ bike24/r2-bike)
if you have 6870 bike you have to upgrade 2 levers ST-R8070-L+ST-R8050-R (295€ bike24/r2-bike)
for non di2 bike - getting di2 cables/batteries etc will be too much trouble

[petromyzon]

I've done it. It's ugly. That bothered me and I ended up buying a disc frame to go with the fork.

[john92]

if you already have R8050 bike you have to upgrade 1 lever to ST-R8070-R (177€ bike24/r2-bike)
if you have 6870 bike you have to upgrade 2 levers ST-R8070-L+ST-R8050-R (295€ bike24/r2-bike)
for non di2 bike - getting di2 cables/batteries etc will be too much trouble

Actually if you just stick with mechanical disc brakes, same levers can be used