Hey, Boys and Girls!

Long-time reader...first time poster here!

I took up road cycling 8 months ago, and I'm loving it. Currently riding a $300 Bikesdirect.com bike- and while I have absolutely no complaints with this bike (I'm really impressed and amazed at what I got for the price) I've always wanted a Klein Quantum (pre 2002, of course)- so I've been looking on Ebay, etc. but I am unsure as to what size I need- and geometry info for these bikes is not so plentiful, and I've read some conflicting info- so I was wondering if anyone on here is familiar enough to give me some guidance?

My current bike is a 54cm and fits me like a glove. Wouldn't want to go any bigger- could go a size smaller and still be comfy, I think.

I'm 5'10". 31" cycling inseam.

Geo of current bike:
Seat tube center to top=54cm
Effective top-tube length=56.5 (semi compact frame)
Head tube length=16.1
Reach=39cm

I'm thinking a 53 or 54cm Klein'd probably do me.....but for some reason, I see very few in that size- most seem to be 56cm or bigger. I've seem some specs that make me think I could go 55 or 56....but naturally, I'd like to know for sure before buying one.

Anyone?

I seem to recall that my 2 Quantums were measured - and marketed, as the TT length being about 1 cm larger then the ST length. Thus my 54 has a 55 ST. Note that these were level top tubes at the time (late 80's and then a '94).

But you should always get the effective TT length if a sloping tube, or the TT length if not, as that's pretty much the determining factor.

So if you are currently riding an effective 56.5, then a 55 or 56 would be withing the range of reason as both are readily accommodated using an appropriate stem to get you to where you are now.

I Believe either a 53 or a 55 will for you. I have a Quantum. Kleins came in odd numbers. 51-53-55-57 I believe. The 55 fits me as well as my Jamis 54 did but it is more of a fit. By the way I love the bike. This is a picture the day I brought it home. It has a different saddle and pedals today but I haven't changed much more. Mine in a 91 with Dura Ace 7400 STI, Derraileurs, seat post, brakes, cranks and hubs.

Thanks, guys!

I guess, adding to the confusion, is that many sellers don't seem to know how to measure properly/accurately.

There was a 56cm on Ebay- seller claimed that the TT was 58.5cm(!) and he gave a seat tube measurement as taken from center of BB to "middle"-


I'm pretty sure I'd be O-K with a 53 or a 55. -And I likely won't buy unless I get a good deal- so if it didn't fit, I should be able to resell it with little or no harm.

NICE bike, Mr. Mobile!!!!!! [drool]

I've never actually ridden one of these babies...but I've just heard so much good about them. Took my $300 BD bike for a short 15 miler today...and I'm still amazed at how well it ride- so I can only imagine what the Klein would be like! (Maybe I'm just easy to please- coming from only department-store bikes as a kid!)

PS. Mobile, looks like you converted that beauty from DT shifters to brifters? That could be an option for me- as frame sets seem to be more common than whole bikes- especially the older pre-internal cable ones. I have a feeling though, by the time I'd buy the rest of the parts, even used...I'd end up with more into it than if I just bought a complete one.

I have wanted a Klein since the first time I saw one. But as you can see mine is pre Quantum Pro. Still the frame was an industry inspiration and in my opinion moved us a bit forward. They had beautiful welds, unlike many aluminum bikes today they took the time to smooth them out so it is hard to tell it was even welded. But Shimano had already come out with the Dura Ace 7400 STI shifter in 1990. In 94 they offered the Quantum Pro and it had Ultegra shifters with internal cable routing. As you can see mine still had the eyelets on the top tube. Some of the Cannondale race bikes came with the 7400STI and by 94 there were a lot of conversions for the derailleur guides. Remember they even had the Stem shifters on some bikes back then as well as bar end shifters.

You can still find 7400 STI shifters on Ebay and I am sure the ultegra shifters are available as well. But if I did it again I might not stick to vintage shifters. The Klein comes with 130mm rear dropouts so mounting a modern wheel is no problem so it will take a 8-9-10 speed cassette if that is what you want.

Gary Klein designed the Quantum with a very stiff rear triangle with big chainstays. When you jump on the prdals for a sprint there is no side flex even if you are a clydesdale. That being said I find using a higher spoke count wheelset and 25mm tires tame the beast for everyday riding. About once a week I bring it to our group rides and I have no problem staying with the group for 40 or 50 miles. It is quieter than my CF bike. As you can tell I am happy with my score on this bike.

Most road bikes with horizontal top tubes tend to be fairly "square" with the top tube length being roughly equal to the seat tube length. So if your current bike has a top tube length of 56.5, then you should be looking at a 57cm frame. A 55cm would be on the small side and a 53cm would not work at all.

Thanks for all the info! I hate being in ignorance- the more I learn about these bikes...the better!

Hmmmm..... From what I've seen, a 57cm would definitely be too big for me- standover height alone (which I think is like 32.5 on a 57) would turn me into a soprano. (I have a 31" cycling inseam)-

Here's the bike I currently have- (The green version- which, for some reason, seems to have a TT that slopes less than the other colors?)
https://www.bikesdirect.com/products/..._al_xi_sc2.htm

Definitely don't want anything that's going to be bigger than my current bike- and to add to the confusion.....some say that the Kleins come in odd-numbered sizes, and yet I've been seeing some with OEM seat-tube stickers which state an even size.......

If I could hear from someone who is my size (5'10" / 31" inseam) and actually rides a Klein....I guess that'd settle the matter- either that, or I'll just have to buy one and try it and go from there. (Unfortunately, you never see a used road bike for sale where I live- much less a Klein; and no real LBS within a two-hour drive- so Ebay and such are my only real alternative).

Thanks for the help.

Oh, and to add to the mes: I found a geo chart for the 57cm Klein- and while the standover height kills it (31.5- not 32.5 as I had stated above), if the chart is accurate, the TT 56.7......which would indeed be O-K. So, I'm thinking a 54/55 would work, and like you say, a 53 would likely be too small....

What adds to all the confusion is that back then manufacturers from different countries had different methods of measuring. Some were center-to-center, some center-to-top, etc. There was a little bit of national consistency (French bikes measured alike, Italians alike, etc.), but you couldn't count on it. So one company's 57 might be another's 56. You really need to know how the frame in question was measured.

Quantum are very small, sub-atomic ..

Exactly! Hence, my question. I don't want to assume that just because my Taiwanese bike is a 54 and fits perfectly, that all 54's will. And then to add to that: When looking at used bikes online, a lot of sellers don't seem to be consistent/have a clue. I've seen them list a bike as being a certain size based on the TT measurement; one specified the size of their Klein as "Large" -some state measurements that just can't be.... and with me being inexperienced..... (Well, I'm getting pretty good at estimating ballpark size just by looking at the headtube and the seat stays...)

Not all the 61cm's I've been seeing! (Although there appear to be books about these bikes which seem to uphold your thesis...and which also imply that riding one of these bikes will have the same effect as an enema- Yep...I've seen 'em- "Quantum Physics"!))

ODD/EVEN SIZE NUMBER ISSUE SOLVED!

Eureka! Just FYI for anyone reading who may find this useful: Just spent some time on Bikepedia researching different model-year Kleins, as I found one I'm thinking of buying (Guy says it's an '01....but it's got the old-fashioned stem, which they stopped using after '98)....

Anywho....checking the available sizes for different years, I see that the Kleins are odd-number sized 98 and earlier...and even-numbered after 98.

So I'm looking at a 55cm....nice purple/green (blue) paint scheme...upgraded to Dura Ace.... $600 + shipping. Says it's near mint. Seems expensive to me....but it might be worth it, rather than spending months looking for a better deal. Had found a '96 in an ugly color (pink/purple/orange), kinda beat-up, and with the original 'Mano 600 components, for $425 shipped...so maybe this $600 deal ain't too bad?

If you trust the seller and indeed it is that clean $600.00 for a Quantum is a good deal. (I won't insult you with how much better I did on my 91.) With Dura Ace it should also be a Quantum Pro, with threadless headset. But compared to my 2008 Jamis Ventura Aluminum my 91 is a much better bike, quill stem not withstanding.

Just my opinion but the early pre Trek Kleins and some of the Cannondales from that time are some of the best Aluminum bikes. There are some modern ones that come close but Gary Klein made a good bike that can be considered a classic. Look up Klein on Face Book and see how popular the Kleins are with their fans. Warning you will se a lot more MTBs but there are quite a few Road Bikes. And the old ones are getting harder to find, no I am not selling mine..

Thanks for the encouragement! I've been wanting one of these since before I even started cycling. I tend to be a little on the frugal side sometimes...I like to get really good deals....but sometimes, I guess it's alright to just spend a dollar or two more, to get something I've been wanting, and just hope it's as-described and what I want it to be.

It's a Quantum Race- it was upgraded at some point to the Dura Ace. It just kills me, 'cause I recently missed out on one like it on Ebay, that ended up going for $480+shipping- but had I bid more....who knows how high it would have gone, right? So this'll be like 200 more (and the Ebay one wasn't D/A..although that's not terribly important to me.)

Here's a pic of my intended: