To Disc or Not to Disc? Old bike U/G for MTB tour

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To Disc or Not to Disc? Old bike U/G for MTB tour

Postby ausdb » Thu May 07, 2009 1:11 pm

Hi All
Many moons ago I used to be in to mountain bikes but then discovered road bikes so the mtb's were consigned to dusty regions of the cave that is my shed. I have since ventured in there and uncovered them and found an old steel framed Barracuda (remember the ones with the oval tubes?) which I am thinking of resurrecting for maybe doing a multi day trip on the Munda Biddi here in WA later in the year at the end of winter.

I have always preferred steel framed bikes and this one fits me well and has brazeons so I can easily fit a rear rack which is a plus. At present it has has V brakes and an XT/STX drivetrain and but only an average old set of Rockshox Indy's. I am thinking of upgrading the fork to something more modern with a bit more travel which will also give me the option of going to disc brakes. I am proficient with an brazing and a oxy torch so fabbing up a disc mount for the rear end will not be an issue.

As the main aim is going to be for a touring bike is it worth going to the effort of changing over to a set of mechanical discs such as BB7's? my reasoning for mechanical disc's is for ease of trail servicing and if I am going to get a new fork I thought might as well plus I can still re-use my old levers. Wheel wise I am looking at using my old rims (217's 32 holes) and finding a cheap set of hubs on that auction site.

Any thoughts or opinions on this? Also suggestions on a suitable fork to look for in the 80mm travel range as I don't want to slacken the head angle up too much.
I guess I could always just buy a new bike but that is harder to get past the chief financial officer plus the frame seems to fit the bill.
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by BNA » Thu May 07, 2009 3:11 pm

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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Nobody » Thu May 07, 2009 3:11 pm

As unexciting as it sounds, I'd stay with the V brakes unless they are causing you trouble with excessive rim wear in the wet etc.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Chanboy » Thu May 07, 2009 6:03 pm

I did a 30k hilly firetrail mtb ride recently on a mtb with mechanical discs. To be frank, since it was dry, I found them no better (possibly worse) then decent V brakes.

If you're going to the trouble of modifying for discs, don't bother unless you're going to use hydraulic calipers.

You will find hydraulic brakes *significantly* better, especially if there is steep down hill sections that require use of the brake most of the time. The force required to squeeze hydraulic brakes is *much* less then mechanical, which will make a huge difference for anything that is endurance distance.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Kalgrm » Thu May 07, 2009 8:24 pm

+1 to Chanboy's and Nobody's suggestions.

To add woe to your cause, you may have trouble sourcing a new fork if the headset on your old bike is a 1" version, rather than the more modern 1 1/8" types.

If I were you, I'd just restore what you have and live with it until you decide you want to get more serious about the dirt.

Cheers,
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby MountGower » Thu May 07, 2009 8:28 pm

I used LX paralellogram V brakes for years nad they worked very well. When building a new 29er recently I was sceptical about the whole disc thing. Particularly maintenance issues with hydraulic systems. I read reviews on mtbr dot com and CRC and went with the BB7s. Whilst I do not doubt that Chanboy has given an honest account of his findings, I can guarentee those mechanical brakes he used were not BB7s.

I was an absolute V brake zealot and took great pleasure in laughing to myself at every sqeaky rubbing brake I passed in the bush and every maintenance head ache thread on this forum. The Avid BB7 mechainical brakes are everything the reviews say they are. They are brilliant and I would say that if you are upgrading the forks anyway and are handy with the torch, then put them on.

They do not rub. They do not sqeak. They are very powerfull. If you have doubts then put big rotors on. I did this to reduce heat on long decents and I get awesome stopping power. I have very good V brakes and these things blow them away. They come on early and evenly, meaning I never feel that I am threshold braking because of how well modulated and early they are.

I use XT levers and cables. 203 front and 185 rear. Not neccessary. Go 185 and 160 on a 26" bike and you'll be fine. Whilst I am very happy with the 8 years sevice I have had from the Vs, I'm no V brake zealot any more and I can genuinely see myself never upgrading (for want of a better word) to hydraulic discs. I am amazed and very happy with my choice.

Go read those reviews. The truth is not a democracy, but sometimes the weight of opinion is so strong that one has to conclude there is something very real going on and I concur. The BB7 is a great choice.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby MountGower » Thu May 07, 2009 8:30 pm

Just read Graeme's post.

That steerer will be an issue. Perhaps full rigid with big tyres? Perhaps not?
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Nobody » Thu May 07, 2009 10:11 pm

FWIW I have also read good things about BB7 and it would be my choice if I upgraded to discs. Hydraulics may have the best feel, but they can have maintenance issues and if they overheat (not likely in AU but you never know) they can hydraulically lock too. AFAIK BB7 are the only disc brakes that are tandem rated.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby mikedufty » Thu May 07, 2009 11:39 pm

I've just changed to discs, mainly because I got annoyed with adjusting V brakes and I'm hoping the discs will be as reliable and trouble free as my motorcycle discs. I suspect they won't be, but so far they haven't broken and are self adjusting well and I'm enjoying the power ($100 a pair diatech anchors).
One thing to be careful of if you go for cable ones is rack mounting. I was originally going to try cable ones but they all seem to have the actuation lever sticking out very far and interfering with getting a rack onto the braze ons. Possibly can be avoided if you are brazing on your own mounts by putting them on the chainstay instead of the seat stay.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby ausdb » Fri May 08, 2009 10:45 am

Thanks for the comments so far, as far as steerer goes she aint that much of a dinosaur as its threadless 1-1/8" up front. The brakes were also never a real favourite on this bike either (non parallelogram v brakes, which I always thought felt wooden) I actually preferred the canti's with grey matter pad s and a really low set straddle cable I have on my old yurt FS bike but thats no good for fitting a rack to.
The BB7 does seem to get good raps and you guys have confirmed it thanks, as for rack clearances it looks like I will have to do some serious playing before I attack the rear end. Now I guess it comes down to finding the right fork at the right price (cheap!!)
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby mikedufty » Fri May 08, 2009 11:15 am

It's hard to find decent new forks with travel less than 100mm now. I was lucky enough to find a FOX 80 off ebay for $200, usually seem to go for about $300.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Kalgrm » Fri May 08, 2009 1:15 pm

Great news about the headtube - that would have been a deal killer for you.

Don't get too worried about destroying the geometry with an extra 20mm on the front. Giant supply the XtC series of HT bikes in the US with 80mm forks while on the Aussie market, the very same frame has 100mm forks fitted. I really don't think it's going to be an issue.

For cheap but good quality forks, it's hard to go past the Rock Shoxs Solo Tora Air. Not the lightest fork on the market, but functions very well and is cheap at ~$380 on Chain Reaction. Get yourself some other stuff there at the same time and you'll get free postage if your order comes to more than $512.

Cheers,
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby tomness » Fri May 08, 2009 3:31 pm

If you are getting a new fork then I would just get an Avid BB7 for the front and keep the back with v brakes. That way you avoid the faff of brazing on a disc mount at the back, and the associated potential rack clearance issues. Plus you can re-use your existing rear wheel.

Avid make very good v brakes as well. I have modded my wifes old hardtail, which had woeful tektro v brakes, to a 160mm rotor BB7 up front and Avid single digit SL V brake on the rear. A pair of Avid speed dial levers enable you to adjust the reach so that both brakes feel very similar. It works a treat and I would recommend it. It is not quite as nice as a set of hydraulic brakes, but it craps all over the hayes cable discs I used to own. Plus it is easy to maintain.

BTW unless you are a heavier rider, or plan on riding downhill trails, or hauling large loads, then you shouldn't need a rotor bigger than 160mm. I have never really had a issue with any bike I've ridden that use 160mm rotors, and that is down some pretty big hills.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Kalgrm » Fri May 08, 2009 7:39 pm

Yeah, but your frame about as much as the bike's, Tomness. ;)

Cheers,
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby trailgumby » Sat May 09, 2009 8:56 am

tomness wrote:If you are getting a new fork then I would just get an Avid BB7 for the front and keep the back with v brakes. That way you avoid the faff of brazing on a disc mount at the back, and the associated potential rack clearance issues. Plus you can re-use your existing rear wheel.

Disagree, with respect. Do it properly. I'd go disc at each end, especially if you can do the frame mod yourself and you're into doing little projects like this for fun, which is the impression I get. Alternatively, A2Z make frame adapters that bolt on, eliminating the need to weld.

The advantage are even feel at each end, which mean less adapting to the feel when swapping between bikes for casual rides after the tour. You will have less worry about braking effectiveness in the wet and mud. The pads last longer. Your primary brake is not taken out of action by a buckled wheel. Plus, the disc front/v rear setup just smacks of dodgy K-mart cheapo throwaway bikes. The disadvantage is that you need disc hubs. Good used wheelsets can be picked up very cheap on fleaBay or at less of a discount new from T7. Don't buy new on fleaBay unless it is a name brand like Mavic or Shimano, et al.

While I use hydro's, if the BB7 cables are as good as the consensus says, then I'd be inclined to go 160mm rotors both ends. Off-road you tend to use the rear brake a lot more (although the front brake is still vital), and I found 185mm on the front with my Hayes Nine hydro's way, way too sudden with 2"-ish tyres and loose surfaces. I can still send myself over the bars with 160mm. :oops:

The downside with any cable-operated rear brake is that in wet conditions the cable gums up quite a lot, whcih is why I have gone exclusively hydro on our disc=braked bikes.

A tip: mount the brake levers as far inboard on your bars as you can. This will allow you to set them up so that you can grip the bars and use only one finger right on the end of the lever. This gives best feel and max power for least effort. Rarely do I sue more than one finger and never more than two.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby tomness » Mon May 11, 2009 7:12 pm

It seems we may have to agree to disagree on this.

The advantage are even feel at each end, which mean less adapting to the feel when swapping between bikes for casual rides after the tour.

Until I actually did the Mod on my wifes bike I would have agreed with you on this issue. However the Avid single digit SL are a very good match to the BB7 in their power, feel and modulation, especially when coupled with the Speed dial levers. I was really impressed with the balanced feel.

You will have less worry about braking effectiveness in the wet and mud. The pads last longer

Agreed. You will loose some braking effectiveness in the wet with v brakes.

Your primary brake is not taken out of action by a buckled wheel

Ummmm You are using your front brake as your primary brake aren't you? After all it is the brake that offers the best stopping power. And you should know how to use it without going over the bars.

Plus, the disc front/v rear setup just smacks of dodgy K-mart cheapo throwaway bikes

This is a personal preference. I think bolting a disc brake mount adaptor to your seatstay, and then having another special adaptor for your rack to clear the disc brake would look far worse than the frankenbrake setup.


Don't get me wrong. I love disc brakes. My wife and I have full hydros setups on our duallies, and I have a set of BB7's on my hardtail. But on her hardtail, she wanted to use a rack, and I didn't want to spend too much time, effort and money improving the braking performance of the bike. The frankenbrake solution worked like a charm.

PS if you go the cable brake route then use full length cable housing. This will minimise issues of cables getting gummed up in the wet.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby familyguy » Mon May 11, 2009 9:09 pm

tomness wrote:
Your primary brake is not taken out of action by a buckled wheel

Ummmm You are using your front brake as your primary brake aren't you? After all it is the brake that offers the best stopping power. And you should know how to use it without going over the bars.


As TG and others will point out, XC riders brake predominantly on the back to eliminate the OTB menace (sadly this didnt prevent TG's injury, read all about it elsewhere). This however may not be efficient or required for your trail ride. Generally speaking, its only down hills that you'd use this technique. Someone far dirtier than me may correct me, but I think thats what TG is saying here.

The reasoning about losing a primary brake through a buckled wheels holds true in that case. Not knowing the trail, and how flat it may be, this may not be as big an impact as others think.

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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby Kalgrm » Mon May 11, 2009 10:00 pm

familyguy wrote:As TG and others will point out, XC riders brake predominantly on the back to eliminate the OTB menace

Not for me - the front brake is the one I use primarily for stopping. OTBs for me have nothing to do with which brake I've used - they result from poor skills and weight distribution. :oops:

The rear one is the one I use to help control direction. It's not effective enough to stop me on dirt when I'm braking to wipe off speed, but it can help stabilise a turn.

Cheers,
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby trailgumby » Mon May 11, 2009 11:06 pm

tomness wrote:
Your primary brake is not taken out of action by a buckled wheel

Ummmm You are using your front brake as your primary brake aren't you? After all it is the brake that offers the best stopping power. And you should know how to use it without going over the bars.

All good comments from tomness.

Yes, I am using my front brake to do most of my stopping, but I'm modulating constantly as the front wheel goes over tree roots, ruts, the bottom of rolloffs and drops, and ploughs through gravel, sand and dust.

However, the rear is the one that gets more constant use for controlling speed and setting up the bike, as I can keep on it when I need braking force over the more challenging bits since it's more forgiving of traction loss and rough stuff without wanting to dump me off the bike. I agree it doesn't pull me up anywhere near as hard. I think most mtbers would wear out their rear pads earlier than their fronts, despite the front being the more effective.

I could get away with losing the front brake and still be able to ride most sections, albeit more carefully and a lot more slowly on aproach. Losing the rear and trying to tackle the same techy sections with just a front brake would be a lot more risky, and see me walking more of the trail. Pic below is one of the moderate sections on my local trail.

Image
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby tomness » Tue May 12, 2009 12:37 am

That looks like some good riding you have there TG. I certainly hope you have not taken offence at any of my comments. I'm also sorry to hear that a fellow mtb'er has taken a tumble. I hope you are well on the way to recovery.

That picture is a bit different to what we have over in Perth. The pea gravel here adds another dimension to braking. Too much use of the back brake results in lots of skids and / or power drifts, neither of which help slow you down much. Mind you a good power drift can help hook you round corners, whilst keeping most of your speed (Note this isn't a practice I should condone).

Obviously I concur with you that the best use of brakes is to use each brake in a constantly regulated manner applicable to the terrain. For me though, due to our lovely gravel and the masses of traction that it offers, I would not want to rely on just one brake. But if I was reduced to just one then I would rather limp home with a front brake only.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby trailgumby » Tue May 12, 2009 8:29 am

tomness wrote:I certainly hope you have not taken offence at any of my comments. I'm also sorry to hear that a fellow mtb'er has taken a tumble. I hope you are well on the way to recovery.


Nah, not at all mate. No worries. Like I said, all good advice from you. :D

The shoulder reconstruction is day after tomorrow. Meanwhile, I got me some system documentation to finish.
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby familyguy » Tue May 12, 2009 9:58 am

Kalgrm wrote:
familyguy wrote:As TG and others will point out, XC riders brake predominantly on the back to eliminate the OTB menace

Not for me - the front brake is the one I use primarily for stopping. OTBs for me have nothing to do with which brake I've used - they result from poor skills and weight distribution. :oops:

The rear one is the one I use to help control direction. It's not effective enough to stop me on dirt when I'm braking to wipe off speed, but it can help stabilise a turn.

Cheers,
Graeme


I did say predominantly to eliminate the possibility... :(

Pea gravel sounds like fun! Super dooorrrriiiiiftuuuu!

Jim
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby cobba » Tue May 12, 2009 3:13 pm

This diagram might come in handy if you do attach a brake mount to the rear stay:

http://www.hayesdiscbrake.com/pdf/Rear%20QR%20IS.pdf
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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby matt#73 » Tue May 12, 2009 4:35 pm

Dont know if you are still considering this project but I have read through this and it sound very simular to my brother inlaw. In my opinion you should cut your losses and buy a new bike. You can get a good basic hard tail say Avanti with Hydraulic disc brakes and a pair of oil front shocks for about $1000, maybe better with runouts. I just think all this work for an old frame you will then start having teething problems which will be frustrating on enduro events. (plus will weigh heaps less)

Just my Thoughts

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Re: To Disc or Not to Disc? Old bike U/G for MTB tour

Postby ausdb » Wed May 13, 2009 12:54 pm

Yes I have been reading and watching this thread develop and this is going to be a long term project. The other reason for staying with the old one is that a new bike is harder to get past the finance minister (wife) and I don't ever plan to race so I am happy with the old bike.
Cheers all for your comments, I will probably look for the forks first then work on the brakes.
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