I could just be ignorant but couldn't the whole 1.5" head tube issue be solved by just making the outer diameter of the head tube larger? Instead of making it out of 3/16th thick tubing make it out of 5/16th or 3/8ths. This would solve the problem of ovaling without the need to redesign the whole fork-head tube-headset connection. It would also provide more surface area to weld the head-tube to the frame. A larger bowl in the bottom of the headset could accommodate larger bearings and support more of the fork crown, thus nullifying the need for a whole new design. I have no need for a 6" single crown but I'm sure there are those that do. This crazy idea of mine would solve the problem with the least amount of effort, or am I missing something? or is this a marketing scheme?
1.5 " headtube
- Thread starter mtbikers
- Start date
Its a marketing scheme. There is no need for a 6+ inch single crown fork when double/triple crowns work just fine on up to 12 inches or so.
I agree that the fork benefits aren't necessarily there. We don't NEED a 1.5" steer tubed fork.
We do need a stronger head tube interface all around. Here's the answer to the initial question. On an aluminum frame, no matter how thick the head tube is, a 1 1/8" headset/headtube combination will allow the head tube to ovalize given a good impact. These impacts are well within the realm of what can be created with a longer travel DH fork. The issue is with the amount of contact between headset and head tube. 1.5 increases that amount of contact both with increased diameter of overlap, as well as increased depth of overlap. We're looking at serious benefits here that DO NOT AFFECT COMPATIBILTY!!!! You CAN run a 1 1/8" fork on a 1.5" head tube and still reap the benefits! Dual crown forks will stay 1 1/8" as there is no need for an oversized steerer tube on them. Steel is another story as far as headtubes resisting ovalization, but with the popularity of Aluminum, we need a solution, and this will be it. Let me recap:
Larger overall contact between headset and head tube,
NO compatibilty problems running 1 1/8" forks,
Larger headset bearings,
Larger head tube contact area on the frame.
What's wrong with it?
Keep in mind I'm ignoring any issues regarding 1.5" STEERER tubes.
We do need a stronger head tube interface all around. Here's the answer to the initial question. On an aluminum frame, no matter how thick the head tube is, a 1 1/8" headset/headtube combination will allow the head tube to ovalize given a good impact. These impacts are well within the realm of what can be created with a longer travel DH fork. The issue is with the amount of contact between headset and head tube. 1.5 increases that amount of contact both with increased diameter of overlap, as well as increased depth of overlap. We're looking at serious benefits here that DO NOT AFFECT COMPATIBILTY!!!! You CAN run a 1 1/8" fork on a 1.5" head tube and still reap the benefits! Dual crown forks will stay 1 1/8" as there is no need for an oversized steerer tube on them. Steel is another story as far as headtubes resisting ovalization, but with the popularity of Aluminum, we need a solution, and this will be it. Let me recap:
Larger overall contact between headset and head tube,
NO compatibilty problems running 1 1/8" forks,
Larger headset bearings,
Larger head tube contact area on the frame.
What's wrong with it?
Keep in mind I'm ignoring any issues regarding 1.5" STEERER tubes.
By the way, the people who are having real trouble with this are those who are retooling to use the larger headtubes... that's going to be expensive. IF they were out to screw everybody with a marketing scam, it'd be something that didn't cost THEM so much.
One minor detail: there is already an oversized headtube/headseat/steer tube standard: 1.25"
Every "reason" cited for 1.5" (except for 6" travel forks) was cited as justification for 1.25" stuff, and it was used by Gary Fisher, Alpinestars, Cannondale, Manitou, etc... in their framesets. The weld junctions were stronger, the steer tubes were less flexy, the bearings lasted longer, yada yada yada...
Every "reason" cited for 1.5" (except for 6" travel forks) was cited as justification for 1.25" stuff, and it was used by Gary Fisher, Alpinestars, Cannondale, Manitou, etc... in their framesets. The weld junctions were stronger, the steer tubes were less flexy, the bearings lasted longer, yada yada yada...
I'm not talking weld junctions, although there's a benefit too.
1.25 didn't take off because it was here at the same time as 1 1/8" came along. Just didn't fly.
Besides, your post doesn't demerit 1.5" at all. So where's the problem here?
I quess this is what it comes down to for me, is there an end to this? I see a need for 1.5 when you look at the new Monster T at 11" of travel, that's alot of leverage against a head tube but only the crazy or the "image is everything crowd" is going to have such a thing. I know my normal Monster T put alot of leverage against my headtube but if you get a strong headset ie King or FSA's Pig you shouldn't have trouble with todays frames. I have seen a friend of mine go through 2 M1 frames last season because of headtube issues but Intense knew they had a headtube issue. So after 1.5 is there 2? or does 1.5 just go away as a not needed idea?
Deep cup headsets won't help. Engineers have pounded out the numbers to prove all this. It may help if Obiwan-f1moto chimed in here.
When designing something, you are restricted by a number of variables, not just one. It is a combination of price, strength, weight, and ease of manufacture that have a lot to do with why it's 1.5 and not 1.3 or something.
I see a need for 1.5 as frame technology increases to allow frames to be more durable. When you own a frame for 2-3 years, with 1.125, you're going to have problems if it's aluminum. A DH fork (Boxxer, Super T, Monster T, whatever) and a hard hit will have enough force to damage even the thickest aluminum head tube!
Please, do your research and reach a logical conclusion about 1.5. Nobody's trying to screw you. In fact, a 1.5 compatible frame fits more forks than a 1.125". Food for thought.
This has been discussed to death, just look my links below.
Also do a search about the subjest as well.
this is an interesting subject. one that i know very little about.
first off, NOTHING will stop people from breaking stuff.
as soon as they build a stronger bike, someone finds a bigger cliff to jump off.
what if they made the bearings like they do in the bottom bracket? so instead of the headset cup being pressed into the headtube the whole bearing configuration sits indside the headtube.
i'm sure i'm not the first to have thought of this, so there must be a reason they don't do it.
didn't klien or some company have HUGE headtubes awhile back?
first off, NOTHING will stop people from breaking stuff.
as soon as they build a stronger bike, someone finds a bigger cliff to jump off.
what if they made the bearings like they do in the bottom bracket? so instead of the headset cup being pressed into the headtube the whole bearing configuration sits indside the headtube.
i'm sure i'm not the first to have thought of this, so there must be a reason they don't do it.
didn't klien or some company have HUGE headtubes awhile back?
I think the 1.5" headtube bikes will be stronger. "The problem" here, if any, is that the 1.25" bikes were stronger, too, there are already parts and tubes and etc... to support that size, and the progenitors of the 1.5" haven't spoken to the 1.25": ie why not just return to the 1.25 rather than spec something most manufacturers will have to tool up for? -- Some would say that last point is the point...
I'm mostly just grumpy that my left-over King 1.25" sets have no prospective homes... and that my ride of choice --XC/HT-- will likely be restricted to flexy 1.125" when the time comes to replace frames...
To be honest, I havent thought about 1.5 as much as I probably should have, but someone has come to me and said "Do your trials frames have 1.5 headsets? If not, can you make one?"
I think we have to look at what the problem is. For me, it seems that ovalising of head tubes is the biggest problem, and I believe increasing the diameter of the head tube won't fix it. I see the problem in the general quality and design of most headsets, NOT in the current standard. If you have a crap cartridge bearing headset pushed badly into a cheap, already out of round out of the factory, sloppily reamed and faced headtube - guess what? Your headtube is going to ovalise. Does your average bike rider know what a loose headset is, especially when its easy to mistake for fork bushing play? Guess what? Another ovalised headtube!
Now I pose the question - Has anyone ovalised a frame with a Chris King Steelset installed? Is there an easy way we can modify the existing standards first to solve the problem? Does anyone even want a 6" travel single crown fork anyway?
Anyway, I know how these things go anyway - marketing rules over smart design, and if companies can sell you some new crap that you probably dont need, then they're going to do so. Improving frame quality and headset quality obviously isnt an option, because instead of spending us300 bucks on a better frame and headset, most consumers would prefer to spend the extra us600+ on a totally new fork as well, which more than likely wont fix their problems
Its irrelevent whether 1.5 is the best solution, because ultimately you'll vote with your wallet. My vote goes for better 1 1/8th headsets, and better quality frames.
I think we have to look at what the problem is. For me, it seems that ovalising of head tubes is the biggest problem, and I believe increasing the diameter of the head tube won't fix it. I see the problem in the general quality and design of most headsets, NOT in the current standard. If you have a crap cartridge bearing headset pushed badly into a cheap, already out of round out of the factory, sloppily reamed and faced headtube - guess what? Your headtube is going to ovalise. Does your average bike rider know what a loose headset is, especially when its easy to mistake for fork bushing play? Guess what? Another ovalised headtube!
Now I pose the question - Has anyone ovalised a frame with a Chris King Steelset installed? Is there an easy way we can modify the existing standards first to solve the problem? Does anyone even want a 6" travel single crown fork anyway?
Anyway, I know how these things go anyway - marketing rules over smart design, and if companies can sell you some new crap that you probably dont need, then they're going to do so. Improving frame quality and headset quality obviously isnt an option, because instead of spending us300 bucks on a better frame and headset, most consumers would prefer to spend the extra us600+ on a totally new fork as well, which more than likely wont fix their problems
Its irrelevent whether 1.5 is the best solution, because ultimately you'll vote with your wallet. My vote goes for better 1 1/8th headsets, and better quality frames.
The one point five standard was started by a suspension company (Manitou). They started it to strengthen the forks. The only problem with headtubes ovalizing needs to be taken care of by individual companies making their frames strong enough.
Longer travel forks need to remain DC. How many motorcycles do you see with SC forks?
Longer travel forks need to remain DC. How many motorcycles do you see with SC forks?
Need I say it again? It doesn't matter whether you have a 2cm thick head tube, with your standard headset in an aluminum frame it is possible AND likely that with a DH fork or long travel freeride fork you will exceed the force to ovalize a headtube, just from the force deforming the metal. This isn't LIKELY or COMMON, but it's one less thing to worry about with 1.5.
As far as being against 1.5, I see no reason to be. There really aren't any downsides like compatibility, since it will fit MORE headset styles than 1.125 does now, and MORE forks than 1.125 does, meanwhile strengthening head tubes and allowing the use of larger bearings. If manufacturers choose not to use them, they don't have to, and those who do may, and will reap the benefits. It doesn't affect any consumer negatively in the end, nor will it affect any company negatively in the end, so what's the opposition about?
As far as returning to 1.25, another reason for 1.5 was to differentiate freeride/downhill bikes visually from cross-country bikes. This would create better product differentiation and hopefully reduce the misuse of XC bikes for freeride (and therefore unneeded frame failures). People didn't go for 1.25 when it came out, nor would they now.
I really wish the corporate bodies involved with 1.5 would do a better job of educating the public. If the public was told more than "1.5 is better because it's bigger", they would be more receptive.
Take this for what it's worth. I'm not really biased in any direction, but educated myself on the topic enough to know the FACTUAL information about 1.5.
I do not meen this as an attack, but if you are as educated on the subject as you claim, you will know that the 1.5 standard was ORIGINALLY started because of problems with fork strength, not frame strength. Yes, you do seem to know what you are talking about. I did not say anything to the contrary of what you claim. You said it yourself; "This isn't LIKELY or COMMON". Then why do it? Why fix something that isn't REALLY a problem? I don't think anyone is actually against the idea. I think most of us just question the necessity. In no way am I trying to argue. Just read a little more carefully next time. Please, don't make assumptions on our education on the subject. Some of us might actually know what we're talking about.
for more info:
http://www.onepointfivestandard.com
JUST RIDE
for more info:
http://www.onepointfivestandard.com
JUST RIDE
Actually, I think my problem with 1.5 largely stems from the fact that there are about half a dozen standards I'd like to see introduced, and making a bigger headset standard isnt one of them. You mention that 1.5 was started by Manitou? Gee a fork company initiating a new standard! I wonder why they'd bother! What you are looking at is another way to sell more forks, headsets, new frame etc. Its motivated more than likely by companies wanting to avoid litigation, as its a hell of a lot easier to build a 9lb hardtail frame and call your agricultural bikes 'burly' than it is to actually educate people.
Standardisation is generally good for the industry, and personally, I dont really care about standards that affect a small percentage of the industry- especially when its simpler to get everyone to increase the press depth of headset cups, increase the angle on angular contact cartridge bearings a la King, and if you're going 6"+ travel, use a dual crown. Problem solved.
Now seeing we've all got so much energy to waste, how about we pressure Shimano so we can up the size of rear axles ( stepped cassette body anyone?), maybe introduce a larger disc mounting diameter while we're at it. Hey, how about we go 9speed, but back to the older, 8speed size chains? Hey, what about a new 145mm rear spacing so wheels actually stay straight.
Do I have to go on?
Standardisation is generally good for the industry, and personally, I dont really care about standards that affect a small percentage of the industry- especially when its simpler to get everyone to increase the press depth of headset cups, increase the angle on angular contact cartridge bearings a la King, and if you're going 6"+ travel, use a dual crown. Problem solved.
Now seeing we've all got so much energy to waste, how about we pressure Shimano so we can up the size of rear axles ( stepped cassette body anyone?), maybe introduce a larger disc mounting diameter while we're at it. Hey, how about we go 9speed, but back to the older, 8speed size chains? Hey, what about a new 145mm rear spacing so wheels actually stay straight.
Do I have to go on?
The fact is, it happens a lot. And when it does, your frame is done. If you'd been running a 1.5, you'd still have your investment.
Yes, everyone could run a Chris King Steelset, but even with a cheap aluminum headset 1.5 is stronger, and in the long run cheaper. It cost me $200 to have a steelset put in my DH bike... Most people don't want to put $200 into an entry level freeride frame, but they are also the ones that can't afford to replace that frame when it ovalizes. 1.5 makes it easier for frame and fork manufacturers to build strong enough equipment at a lower price.
Please read the discussions in Sandman's links. They have a full explanation/criticism of both the marketing and the engineering behind the 1.5 standard. Sandman and I disagree on the economics of 1.5, but I'm pretty sure we agree on the engineering...
edit: these are the links I was thinking of --
1.5 poll
1.5 discussion #1
Sorry if I was a bit aggressive. I don't know how many times I've posted about 1.5 alongside others, and people still question it. Opinions are allowed, but use facts to back them up.
The unlikely or uncommon seems to happen enough that I see it pretty often. I mean, it's not SUPPOSED to happen, everything being perfect and ideal, but it does, due to tolerances, due to rider error that was unavoidable, or other circumstances. The way I see it, with 1.5, there is more room for error as far as the rider goes, and one of the many goals is to increase tolerances to eliminate head tube problems due to ill-fitting headsets.
I tend to focus on the head tube/headset side of this rather than the fork, because steerer tube strength isn't an issue for dual crown forks, and it isn't an issue given a well-built fork designed for the abuse the rider dishes out. Head tube strength still can be.
As far as individual manufacturers taking care of head tube problems, how are they to do that without standardizing the process? Standards allow consumers to not worry about their parts fitting. They can have confidence that when they buy a 1.5 headset for a 1.5 frame, the two will go together. If each frame manufacturer did something else, or started patenting things, we'd have major problems (Think ISIS versus Octalink, but worse).
I agree that the fork benefits were probably one of the main reasons for 1.5, but as I see it most people who want 6" of travel will ride a dual crown, and those who want 5 or less will ride single. Those who ride really hard realize they need dual crown. I think a 6" single crown fork will have its uses, but I like to think Manitou used that as a way to draw attention to the 1.5 Standard as a whole, and that fork strength was not the only design criteria.
I certainly wasn't attacking you or anything, and I'm not one to flame. I'm having a debate here, and I get into it a bit.
I WANT people to agree with me (doesn't everybody?), but if they don't, that's no biggie.
I saw next years Cannondale Gemini yesterday. The 1.5 standard looks very sexy. It had a Cane Creek headset and a pretty Bomber fork. I was so turned on when I saw the 8" hayes rotors I wanted to spooge all over it.
Who would have thought that Cannondale knew how to build a bicycle? It surprised the heck out of me.
As long as they don't try anything funny with xc bikes I got no problem here.
Not a Cannondale Rider
Who would have thought that Cannondale knew how to build a bicycle? It surprised the heck out of me. As long as they don't try anything funny with xc bikes I got no problem here.
Not a Cannondale Rider
if we adopt the 1.5" standard why not a 1.75" standard that way we never have to revisit this issue again in the future? Just a thought. But it seems to me we need to ask ourselves were does this end. when is enough a enough? And most important of all will I be able to get a cheap adapter for my Monster T so I don't have to replace that fine fork, I really love it and feel it has saved my life more then once. It would be a shame to have to buy another when this honey has been so good to me.
That's the idea here, I suppose. There is a plateau of riding possibilities in the future as far as impacts on the bike. From there I have a feeling it gets to technical aspects. I believe 1.5 would be the end, as it's just one less thing on the long list of things to worry about.
As for an adapter for the Monster T, it's been said (by myself and others) time and again that a 1.125 fork will fit a 1.5" head tube. Cane Creek already makes a headset that does the conversion, and most frame makers will include reducer cups that allow you to run a 1 1/8" headset.
Anytime man. Feel free to PM me with any questions you have if you feel I could answer them!
Cool, its backwards compatible. That means its almost as bad as Gary Fisher, but not as bad as Shimano. 
IF you think about it, a 1.5" head tube will now fit more forks than a 1.125, since 1.5" steerer tubed forks will not work with a 1.125" head tube. In theory it could also fit 1.25, though nobody has jumped on that bandwagon.Originally posted by Thylacine
Cool, its backwards compatible. That means its almost as bad as Gary Fisher, but not as bad as Shimano.
Here is a few more, that will help shed some light:
RM Thread 1
RM Thread 2
RM Thread 3
Hope this helps.
I've heard from a reliable source that Turner will be unveling 1.5 head tubes at Interbike.
I was told to keep it quiet, but aw hell...
I was told to keep it quiet, but aw hell...