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Ciufalon 06-12-09 01:37 AM

Question about 4130 Bridgestone MB3
I figured this forum would be the best place to ask this question since the folks here are knowledgeable about tubing. I have a 1986 Bridgetone MB3 that is made of straight gauge 4130 and I am thinking of turning it into a touring bike because it fits great, is really comfortable, has long chain stays, and I think suitable geometry. I assume the tubing is of fairly good quality since it is a Bridgestone. Can someone confirm if 4130 straight gauge is good tubing that would be suitable for a strong touring bike with 26" wheels? I know it might not be the lightest, but it is not extremely heavy and I will just have some additional braze-ons put on the bike by a framebuilder. I have road touring bikes, but want a more stout tourer with 26" wheels for some places. Thanks for any helpful insight you can provide me with.

rodar y rodar 06-12-09 05:47 AM

I can`t say about that specific tubing, but my touring bike is an mtb in drag with 4130 staight gauge tubing. And no, it isn`t the lightest, but at a tad under 30# it`s ALMOST the lightest at my house. Maybe I should worry more about it, but I don`t.

Ciufalon 06-12-09 03:25 PM

Thanks rodars. I was really just wondering if cr-mo 4130 is generally considered to be good quality bike tubing and it sounds like it works fine for what I have in mind. Good to hear. Just didn't want to spend money to add the little touring specifics to the frame if it was not a wise thing to do.

LeeG 06-12-09 08:37 PM

My recollection is that the bike is well built and not too heavy. 4130 is your basic do all chrome-moly tubing. It's what Surlys are made of and other production and custom bikes. I have a custom 26" wheeled touring bike with a 4130 rear triangle and Reynolds 531 main triangle and forks.

NoReg 06-12-09 09:28 PM

" I was really just wondering if cr-mo 4130 is generally considered to be good quality bike tubing "

In a sense possibly no. Since some people will interpret quality as referring to the degree of refinement or superiority of a particular product, where 4130 is the bottom of the barrel of lightweight tubing. But 4130 straight gage (particularly older tubing) is normally just some aircraft tubing, and as such is everything you could possibly want, in so far as quality control is concerned.

I actually think there are advantages to straight gage tubing for touring. First, for serious heavy duty touring bikes there is little reason to use anything much fancier than either 4130 straight gage or butted 4130 tubing (generic or branded) (no harm in anything fancier necessarily but little realizable improvement). So lets say you have a 24" tube with 4 inches of butt on either end. You would save 3 ounces in the butted tube. It is likely only two tubes that will be butted in the main triangle, A straight tube frame may be butted in the seat tube, or it may not same with a butted frame. So the overall difference in weight is 6-9 ounces. Every other part is untouched. Most tapered tubes (chainstays, seatstays, forks) are actually going to be the same, though there could be degree of refinement differences, but they will all be specialty bike tubes either way (or straight gage 4130), and they tend to be generic unless they are fairly fancy tubes the likes of which do not necessarily make it on even 4K bikes. But anyway, with straight gage we are just talking about a 6-9 oz difference. On a bike that may with gear weigh 100 pounds. As against that 6 ounces, there are advantages to the heavier stuff; it rides nice; it is stiff; it takes all the bobbles you could want to braze on; it adapts to more take down arrangements with full strength; less prone to damage during shipping; nice solid base for all the heavy water bottles; less prone to rust through...

When I build a personal frame with 4130 straight gage it actually doesn't save me any money. There is no cost difference in getting aircraft tubing, and ordering 4130 butted from Nova from where my tubing has to come to. So it is just a choice based on the sort of bike I want.

Also, if you hang out on the boards and hear big name people talking proudly about the bikes they make there can be a lot of either 4130 butted or straight gage that lands in the bikes of some fancy NAHBS winning types, for sure the last two years, and one of the earlier years also. Could be others, only know 3 of the years winners, by online rep.

I don't really feel comfortable on MTB geometry bikes for road use, but many do. They have some features of a touring bike, but not others. As long as you will be comfortable they are a good choice.

Ciufalon 06-13-09 08:49 PM

Thanks for helping me to better understand about my bike and the choice I am making. It sounds like it will make a good heavy duty 26" touring bike. The reason I thought of going this route is the bike feels almost custom built for me. Unlike other mountain bikes it has a shorter top tube but with long chain stays, which suits me well because I have long legs and short torso. It sounds like it will amount to just was I was hoping for. Something along the lines of a LHT, old specialized Stumpjumper, Riv, etc. Weight was not my main concern, more strength, quality, and durability for a touring bike that can handle touring in less developed regions and have 26" wheels. I admire the work framebuilders do and all the knowledge and skill that goes into the craft. For my plans, the tubing sounds as refined and superior as I want and need. I appreciate you all sharing your knowledge.

noglider 06-16-09 03:57 PM

You speak so highly of the comfort and fit of the bike, which means it's the right bike for you!

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