Mountain Bike Reviews Forum banner
1 - 12 of 12 Posts

·
a.k.a. MTBMaven
Joined
·
1,750 Posts
Discussion Starter · #1 ·
Sorry in advance if this topic has been answered before. There are two difference size thicknesses for cable housing, I'm pretty sure the two sizes are 4mm and 5mm. Why would one go with one versus the other?

Once I has a shop install cables on my bike before I learned how to do it myselft. They installed the thicker 5mm housing. Ever sense then I've been using the thinner 4mm.
 

·
Old man on a bike
Joined
·
12,395 Posts
Generally 4mm is for shift housing, 5mm for brake housing. The two types of housing aren't constructed the same and generally you don't want to use shift housing for your brakes (but some do it).
 

·
Banned
Joined
·
7,131 Posts
The last poster is wrong, there's both 4 and 5mm shift housing. Most shops will use 5mm, and there's no real good reason to have two different sizes. The 4mm will save a little weight, but the 5mm is going to be a little stouter.
 

·
Old man on a bike
Joined
·
12,395 Posts
Guess it shows I haven't been hanging out in shops much, didn't realize most use the 5mm now. Maybe I'll get a box next time I buy shift housing...one size ferrule sounds good to me.
 

·
Registered
Joined
·
1,740 Posts
5mm has been the standard since as far back as I remember. 4mm was another Shimano innovation for no good reason.
Bikinfoolferlife said:
Guess it shows I haven't been hanging out in shops much, didn't realize most use the 5mm now. Maybe I'll get a box next time I buy shift housing...one size ferrule sounds good to me.
 

·
Old man on a bike
Joined
·
12,395 Posts
Learned something new, didn't realize that 5mm was the standard before Shimano reinvented it. While we're on the subject, do you guys recommend any particular brand or is the qbp stuff good enough?
 

·
Do It Yourself
Joined
·
5,720 Posts
Bikinfoolferlife said:
Learned something new, didn't realize that 5mm was the standard before Shimano reinvented it. While we're on the subject, do you guys recommend any particular brand or is the qbp stuff good enough?
Jagwire makes most of the cables and housing used today. That includes QBP, Shimano, Avid and more. Generally speaking, it's all about the same and QBP works great.
 

·
Registered
Joined
·
2,850 Posts
lebikerboy said:
5mm has been the standard since as far back as I remember. 4mm was another Shimano innovation for no good reason.
I'm not sure Shimano "invented" this but there are more than no good reasons for it. 4mm housing does bend a bit easier. Its more flexible and easier to route easier. The inside diameter is smaller and more snuggly fits standard 1.2mm cable. 5mm housing inner diameter is slightly wider (can typically even fit brake cables). The cable is slightly loose inside and this tends to introduce some slight cable slop. Especially when the cable is bent such as turning the bar or suspension movement. It also makes it easier to use sealed rubber ends. I've never found any 5mm cable to perform as well as your average generic 4mm stuff. Generally speaking this is housing we're talking about here. There's no huge reason to jump to 4mm but there's certainly no good reason to stick to 5mm at all.
 

·
Banned
Joined
·
7,131 Posts
Hecubus said:
I'm not sure Shimano "invented" this but there are more than no good reasons for it. 4mm housing does bend a bit easier..
That works both ways though, easier to bend means it's less stout and the stiffer and stronger the housing is, the better your derailer will work and shift. I think the "better shifting" with 4mm would be a placebo effect type thing. Standard shimano housing on nice derailers and such comes as 4mm, and it usually goes on nice bikes. On nice bikes the owner usually takes the time to tune it correctly and make it work right.

Also, don't think that all bikes are even using shift housing where they are supposed to be, cheap bikes use brake housing instead of shift housing because it costs 1/3rd the price, but it makes them perform like crap. More than a few home mechanics have used brake housing instead of shift housing as well.
 

·
Registered
Joined
·
2,850 Posts
Jm. said:
That works both ways though, easier to bend means it's less stout and the stiffer and stronger the housing is, the better your derailer will work and shift. I think the "better shifting" with 4mm would be a placebo effect type thing. Standard shimano housing on nice derailers and such comes as 4mm, and it usually goes on nice bikes. On nice bikes the owner usually takes the time to tune it correctly and make it work right.
By easier to bend I mean it seems less likely to kink on tight turns and keep cleaner bends. That would not affect shifting (should help a bit if anything) as long as the cable remains well made and incompressible. Theres a difference between flexibility and incompresibility. I find 5mm to be more of a pain to use on bikes with weird routing or poorly placed cable stops. I don't think there is any significant difference in the internal wiring structure of the two sizes which is what makes it resistant to compression. The internal diameter on 4mm is just smaller so everything is brought closer together, to keep the cable from having play inside. 5mm is probably just a carry over from older days using the same cable diameter for brake and shifting. If you think about it there's no point any more in using cable meant for a 1.6mm? ID cable when standard shift cables are now 1.2mm.
 

·
The Vandal strikes again
Joined
·
132 Posts
With respect to using shift housing for brakes, this is always a bad idea. Yes, it makes the brakes feel much more firm, but it eliminates the rider's ability to modulate brake power. This effectively turns the brakes into on/off switches. The second problem is that because the shift housing cannot compress under heavy brake lever force, the housing can simply split open. It's no designed to withstand those kinds of forces. Not such a good event mid-ride. If someone is trying to make their cantilever or v-brakes feel more powerful, they should first true the wheel, then shorten the length of brake housing so that there is no excess but still enough to spin the bars around in a crash, then properly align the pads with the rim and minimize the gap between rim and pads. If necessary, replace the old housing and cable with new to eliminate drag from dirt contamination. But do not use shift housing for your brakes.
 

·
Registered
Joined
·
114 Posts
I prefere 4mm housing on my bikes, especially my 9 speeds. Seems to be slightly more precise (not noticable on the 7/8 spd), but primarily I like it because the 4mm ferrules we have seal MUCH better than any 5mm ferrule I've seen. Wipe the cable with a little polylube or even just wipe it down with Pedro's Bike Lust and it stays nice for a while.

Nothing against the 5mm stuff, it works fine (and like I said, especially with 7 and 8spd set ups), but I prefere the better sealing of the 4mm ferrules.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top