2025年7月25日星期五

"浸"數呔 (輪胎層級), 何為"浸"數? Ply rating in commercial tires

 *English version below*

曾經有兩個電話 (懷疑係同一人) 打黎, 

第一人

👨: "您地貨van呔係咪8浸呔, 要8浸呔, 貨van先驗到車"
👀: "平時裝開貨van呔夠磅就驗到車喎?"
👨: "係夠磅呀, 不過要8浸"

第二人
👨: "您地有冇8浸呔, 話要8浸呔先驗到車"
👀: "有8浸呔, 唔駛8浸都驗到車"

其實我好少會同啲唔熟既人去爭論一樣野. 都曾經同過一間話自己做車行咁多年既老細, 問佢點解一定要 106/104 先可以驗到貨van. 而佢既答覆只係 "因為驗車個個人講, 我做左咁多年, 就係一定要咁先驗到", 但又答唔到我點解貨van 呔會有兩個負重 106 / 104


係未深入了解 "浸" 數之前, 先講下貨van 一定要 "8浸" 先驗到車呢個問題.
1. 現時市場上被列入輕型貨車系列 :
    a.     電動貨van 日產env-200
        跟車呔係 185/65 R15 92V Goodyear, 係一款私家車呔, 冇浸數.

    b.    現代貨van Staria (新款貨van)
        跟車呔係 215/65 R17 108H, Kumho PorTran KC53,  冇浸數顯示.


    c.    豐田 Hiace 300 
        跟車呔係 215/70 R16C 石橋 貨van 呔, (歐盟標籤顯示只得6浸)


上面全部都唔係 8"浸" 呔, 唔通可以批到有問題既全新車入黎香港銷售?

佢一定係到暗示緊, 215/70 R16C 有好多貨van 呔都過唔到驗車, 包括 石橋, 東洋個啲, 只係得好少啲先過到驗車................................



如果係以前仲用緊有內膽既呔 ("帆布呔", bias-ply) , 就的確係注重 "浸"數呢樣野. "浸"數係"帆布呔"年代, 直接反映出個條呔有幾多層 (結構), 可以負重幾多. 越多"浸"就負重越多.

而家既年代係用緊 "鉛子呔" (可能有啲人會叫 "空心", radial tires). 設計上既物料已經有足夠承托力, 其呔肚位顯示既 "浸"數代表住條呔有幾 "硬正", 已經不再是講緊條呔入面有幾多層.

係香港驗貨van, 都需要跟據輪胎上所示既負重去驗車. 雖然 374A 冇特別提到輪胎負重字眼 (但要裝岩負重係常識吧?), 更沒有提到一定要 "浸數" (只提到有關結構 及適當大小及設計的充氣輪胎), 但由於 "浸數" 已經不再是有關鉛子呔的幾多層問題, 對於負重已無直接關係. (有情況下, 某牌子6浸係有可能負重大於其他牌子的8浸)



如果個位係一名車主的話, 我建議您問多幾十間呔鋪睇下佢地點答您. 反正我講完您都唔會信. 問多幾十間, 您應該自然會信.


-----------------------------------------------------

Over the past years, there were two ppl called up and asked:

First peson

👨: "Does your van tire have 8 ply rating? Only 8 ply rating can pass light goods vehicle inspection"
👀: "The commercial tire that I installed on van have more than enough loading index to pass"
👨: "Yes, but need 8 ply rating"

Second person
👨: "Do you have 8 ply rating van tire? I heard that only 8 ply rating van tire can pass the inspection"
👀: "We got the 8 ply rating, but it is not necessary to be 8 ply for passing."

I rarely argue about something with those whom I am not familiar with. An owner of a vehicle dealer told me that he needs the loading index to be 106/104 in order to pass the inspection. His explanation was "somebody in the inspection center told him it has to be 106/104. I had been in this area for so many years, and this had to be the way", and yet he failed to explain why commercial tire has two loading index. 

Before talking about ply rating, check out the below light goods vehicle to find out about 8 ply rating queries.
1. Nissan env-200 electric van
    Original equipped tires were 185/65 R15 92V Goodyear, a passenger car tire without ply rating stated.

2. Hyundai Staria (new van model)
    Original equipped tires were 215/65 R17 108H Kumho PorTran KC53, without ply rating stated.



    c.    Toyota Hiace 300 
           Original equipped Bridgestone 217/70 R16C R660A, EU label stated it only has 6 ply rating.       



All the above light goods vehicle are without 8 ply rating tires equipped. Is it possible to have a failure equipment approved to enter Hong Kong market for sales? 

Is he trying to tell me that 215/70 R16C only a few tire model available approved to be installed on van.
Those such as Bridgestone, Toyo only have 6 ply rating.




Two/three decades ago where bias-ply tire still in used, ply rating is an important indicator to check if it can be installed. It implies how many layers does a tire have. The higher the rating, the higher load it can support the vehicle.

However, this generation is using radial tires (without anything inside). The design and materials provide sufficient strength to the radial tire (which shows as loading index). The ply rating on the radical tire implies how "strong" the tire is, but it's not about the layers of the tire anymore.

To pass the inspection, you only need to check out the loading index. Although 374A does not clearly specifies tire loading index (but it's common sense right?), nor specify ply rating (only structure of tire and appropriate tire size and design are stated), the ply rating is no longer directly related to radial tire loading index, and hence does not need to check the ply rating for regulation. (some brand with 6 ply rating might even have higher loading index than 8 ply)









2025年7月9日星期三

輪胎胎紋的寬度, 同一寬度尺寸, 為何部分輪胎看似比其他較大或細? (持續更新) Tire width, with the same width size, why some models appear larger or smaller? (to be updated continuously)

 *English version below*

有部分人曾經都提過有關輪胎寬度問題. 新購買同一尺寸的輪胎對比下, 看似比較寬身/窄身.

❓係肉眼上既錯覺 , 定 實際尺寸真係有唔同?  

今次我會幫大家搜羅, 盡量每一個尺寸, 每一款 (就算係同牌子), 唔同製造地點都度下到底條條呔既寬度係咪真係有分別. 

🚙係呢樣之前, 要先幫大家重新了解一下, 輪胎既寬度

**注: 由於係用人手, 用拉尺去度, 一定會有誤差. 另外, 輪胎寬度應該係以裝左上呔鈴, 有足夠輪胎氣壓, 未有裝上汽車前測量. 只可用作為參考之用. 今次只係想睇下, 咁多款呔下其實只係我地肉眼上既錯覺, 覺得一啲呔好似比另一款呔較大/較細.

**特別注意既係, 一款同一尺寸, 同一製造地點, 但唔同製造日期, 係會有機會有輕微誤差. 過去係某啲輪胎廠係根據製造日期批次去回收有問題既輪胎.


肉眼上既錯覺 (optical illusion), 其中必定會了解到 "Müller-Lyer illusion" 及 "Ponzo illusion" - 兩條相同既橫線但看起來好似一長一短, 及兩條相同既直線看起來一高一底.

普通既直線都會令到視覺上產生錯覺. (大部分) 輪胎 (我個人認為) 都係一樣. 胎紋上既設計, 包括主要排水紋及其他周邊細少既槽會影響視覺上睇出黎既寬度.


而呔肚位上所示既寬度, 其實係由一邊既呔肚位去到另一邊既呔肚位, 並非係呔紋既寬度. 所以, 一條 205/55 R16 既寬度為 205mm, 觸地面既呔紋並非係 205mm.

呔肚位所示既寬度有國際認可要求. (下文叫佢做"總寬度"), 但呔紋的寬度並沒有特別固定要求. 但暫時我所量度既呔款當中, 大家呔紋的寬度其實都係差不多相同.

(輪胎所示既寬度, 上圖輪胎尺寸為 205/65 R15)

上圖所顯示的兩款不同輪胎, 其實肉眼上既寬度看似不一樣(相可能睇唔出), 但量度下, 呔紋寬度及總寬度都係差不多一樣. 而總寬度都係205mm




相信唔少人都會察覺到, 係 www.tyrehood.com 能夠俾您選擇既寬度, 每個寬度之間都差 10mm. 
根據European Tyre and Rim Technical Organisation (ETRTO), Tire and Rim Association (TRA) , 每個尺寸製造出 10mm 之差, 其實有多個原因. 當中, 10mm 之差先會令輪胎有些少增加性能(e.g. 咬地性能) 

除此之外, 輪胎寬度都有 "可接受範圍". 應該係大約3%之間. (e.g. 205) 總寬度都有機會可能係 198mm, 211mm etc
有可能呢個原因, 引致部分呔睇落好似有些少窄身啲或寬身啲

問題黎啦 ❓❓❓❓❓❓❓❓❓

Q1: 會唔會每一款既同一尺寸輪胎都會有不同既呔紋寬度呢? 
Q1a: 會唔會每一個牌子其實都有一個特定既標準去製造出呔紋寬度呢?

👀

Q2: 每個尺寸既總寬度都有10mm 之差, 會唔會有部分輪胎尺寸總寬度寫 (e.g. 255), 但實際可能係 250mm? 更有可能係246mm ? 大於"可接受範圍"?

👀

Q3: 有冇可能兩個不同尺寸 e.g. 205/55 R16 vs 215/55 R16, 總寬度相差 10mm, 但呔紋寬度係一樣長?

👀

Ans: 呢個就係我今次會幫大家收集既數據. 下回分解.


1) Bridgestone 石橋 Potenza Sport, 235/35 R19, 歐洲製

呔紋闊度 大約 230mm
總闊度 235mm, 度落好似 240mm (上圖並非度總闊度)


2) Pirelli 派拉利 255/45 R19 Pzero4, 歐洲製

                             (圖1, PZ4 MO)                                                        (圖2, PZ4 T0)

 
   
                           (圖1a, PZ4 MO, 總闊度)                                   (圖2a, PZ4 T0, 總闊度)
                       總闊度: 約 260mm - 265mm                         總闊度: 約 260mm - 265mm
                            度落好似270mm                                                   度落好似270mm

兩者之間明明相同尺寸, 但標記不一. 設計上會有唔同. T0 (專為Tesla 設計, 圖2) 的呔肚位設計近鈴邊位較為突出, 能夠覆蓋原配 Tesla 呔鈴邊. 但MO (專為Benz 計設, 圖1), 呔肚位設計有些少不同, 令到安裝在 Tesla 後凹左少少.

更多有關輪胎標記可以係網站了解更多.

https://www.tyrehood.com/tyremarking.php



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Some have enquired about the physical width of a tyre. Purchasing the same size, why different models look wider or narrower than the other?

❓ Is it an optical illusion, or the size physically really different?


This time I will try to gather as much data as possible, with different sizes, different model and different manufacturing place to ascertain if the width of each tyre (even of the same brand) really has a difference.

🚙But before that, let's understand more about TIRE WIDTH

**Note: There will be a human error in measuring the width of the tire (using measuring tape). The standard of measuring tire width is supposed under the following conditions:

- Has installed on a rim
- Sufficient tire pressure
- No loading.

Hence, this experiment is just for reference with no accurate data. It is supposed to find out if the look of a tire that looks narrower or wider is simply due to optical illusion.

**Another Note: A batch of same size, same model, same manufacturing place but different manufacturing date could have a slight variation on the measurement. After all, tire manufacturer recall tires based on manufacturing date. 


Talks about optical illusion, we will surely come across "Müller-Lyer illusion" and "Ponzo illusion" - Two horizontal lines with the same length but one looks longer and the other one look shorter, 
and Two vertical lines with the same height, but one looks higher, the other one looks shorter.

In this way, I believe that (most) tires that look wider or narrower due to tread design with different styles of rib, block, sipe.


The width of the tyre shown on the sidewall is actually the length between one point of the tyre (inner) sidewall, to the other point of the (outer) sidewall. The width shown IS NOT tire tread width.

Therefore, a 205/55 R16 tyre has a 205mm width. The tire tread width that touch the ground IS NOT 205mm

The measurement of the tire size has an international standard. But tire tread width does not have a fixed standard. So far, the tire sizes that I have measured by now have around the same tread width and overall width.
(Tire width shown with red lines. Both tires are 205/65 R15)

The two tires shown on the above image actually looks physically different in width. (You may not see it inside the photo). But both tire tread width and overall width (which is 205mm) are the same after measurement. 



Some may discover that www.tyrehood.com only allows you to select a width with 10mm increment. According to European Tyre and Rim Technical Organisation (ETRTO), Tire and Rim Association (TRA) , tire should be manufactured at least 10mm difference due to a varies of reasons. One of them is a 10mm difference can only prove to have slight improvement of performance (e.g. traction).

In addition, the width of the tire size also have a tolerance of around 3%. (e.g. 205) overall width, actual physical width could be 198mm, 211mm etc.

As such, this may result in some tire model looks narrower or wider.

 ❓❓❓❓❓❓❓❓❓

Q1: Does each model have different tire tread width?
Q1a: Does each brand actually have their own standard for tire tread width?

👀

Q2: With an 10mm difference in width, will there be tires with size overall width (e.g. 255), but actual physical width is 250mm, or even narrower, 246mm in which greater than the international tolerance?

👀

Q3: For two different size e.g. 205/55 R16 vs 215/55 R16, overall width is 10mm but tire tread width is the same?

👀

Ans: The answer is going to reveal next time after data gathering.



1) Bridgestone Potenza Sport, 235/35 R19, Made in Europe

Tire tread width around 230mm
Overall width 235mm. Measurement looks like 240mm 
(above image does not measure overall width)


2) Pirelli  255/45 R19 Pzero4, Made in Europe

                             (Image 1, PZ4 MO)                                            (Image 2, PZ4 T0)

 
   
                  (Image 1a, PZ4 MO, Overall width)                  (Image 2a, PZ4 T0, Overall width)
          Overall width: around 260mm - 265mm           Overall width : around 260mm - 265mm
                Measurement looks like 270mm                            Measurement looks like 270mm

Both sizes having (should be) the same measurement with different tire labelling, tire design will be slightly different. T0 (design for Tesla), its sidewall near the rim is more extruded, covering up Tesla original rim. On the other hand, MO (design for Benz) the design of the sidewall is slightly different. Hence, it appears to be more inward.

For more details about tire marking, you can access to the below webpage for detail:

https://www.tyrehood.com/en/tyremarking.php



2025年7月3日星期四

正規補呔方法其實係內補? 內補係萬能? The appropriate way of tyre patch is internal patch? Internal patch can resolve everything?

 (English version below)

補呔, 每個駕駛車渣幾年車都一定會試過一次. 您未試過唔代表永遠都唔會. 係香港, 私家車普通中左釘後, 會吉支俗稱"牛筋" 填補個位後, 又續行駛.

但其實, 根據(所有國家)輪胎廠商既維修輪胎指引 

1. 正常補呔方法係內補 

英國, 美國輪胎製造商協會表明, 內補, 先係叫修補輪胎. 係呔出面吉支針落去唔係叫修補.

係香港, 吉"牛筋" 已經係好多年既習慣. 就連您拖車番原廠都係吉"牛筋", 盛惠 $100. 係香港既習慣係要 快 & 平. 拆出黎內補再裝番成個程序需時可能要最快15分鐘. 平均可能30分鐘. 至於內補分為冷補, 熱補個啲我就唔多講.

但呢到既香港, 中釘次數係多過世界各地. 若一條 15" 中國牌子既呔係 $500/條. 車主中左3次釘, 內補既價錢足夠佢買過一條全新既呔. 

而家普通吉支針, 都仲可能玩到兩三年(視情況而定). 兩三年有好多平日渣車既車主都已經玩完一條呔. 仲會想內補?

2. 修補輪胎指引列明太大及呔邊位不能修補

美國輪胎製造商協會列明, 不修補中釘位超過6mm直徑 的位置. 不修補呔肚位/呔邊位(sidewall)及類近呔肚位的位置(下圖紅色圈住).



英國輪胎製造商協會列明, 若修補呔邊位, 需要被真-專業公司去修補. 仲可能需要重新翻新 (可能係加料補番個位)

您又會唔會想跟足? 別人都在吉針就算. 補呔吉針吉得多, 自然所有人都慣左補呔先吉針.

A. 內補係萬能

過去有兩個人打黎問我內補. 話內補唔係萬能既咩. 

如果我答係, 我一定收好貴. 

通常做得內補, 有9成都係我自己同車主提議俾我, 個啲位通常都近呔肚位. 曾經幾次試過用左一個幾小時內補最後又成功左. 仲有個特登渣過黎話俾晒4條呔我試內補呔肚位(就算唔成功都照付內補價錢), 我補左3條, 係最後整左啲野又成功無漏氣. 


B. 未補都仲漏氣, 補完都仲漏氣

不過唔係次次中釘都一定補得到. 仲要唔知點解, 氣呔已經明明無晒氣, 都仲會有氣泡*出現 (睇下圖及影片)

*氣泡既出現係因為入面既空氣向出時遇上出面流入黎既水而做成. 最簡單既理解方法可以睇成魚缸入面既打氣泵, 空氣由氣泵入面出黎, 型成泡再浮向水面

(氣泡出現位置, 影片係下面)

(無晒氣都仲係到出緊泡)
曾經見過私家車呔都有同樣情況

(已經內補完後, 入面無氣, 都仲有泡)
        
補完都仲漏, 好多人見到都一定話補唔到. 但會唔會其實只係呔紋與呔之間仲繼續存在空氣? 



----------------------------------------------

Tire patch, every driver will surely experience at least once after driving for a few years. In Hong Kong, a simple plug from the external tire is a common patch in the private vehicle industry.

Yet, according to tire manufacturer association (from different countries) guideline,  

1. The correct way of tire patch is internal patch

According to British, U.S. tire manufacturer association, internal patch is the right way of repair. A plug is not considered a path.

However, a plug as a patch has become a habit in H.K. Even if you get a tow service to the agent repair center, they will still use a plug that cost you $100. An internal patch may take 15 minutes, or average 30 minutes, which may consider a long time for some HK drivers.

In addition, tire leak due to nails and screw happened more frequently than any other parts of the world. If an 15" China brand tyre only cost $500/tyre and a vehicle owner got a internal patch 3 times, the price for the patch can get him a new tyre.

Afterall, a plug may last 2 to 3 years (depending on situation). Most drivers may have their tire tread worn over these years.

2. Tire repair guideline states a size and sidewall cannot be repaired

According to U.S. tire manufacturer association, puncture injury cannot be over 6mm diameter. Repair areas limited to tread area only (picture below circle area is not considered puncture repair area).


British Tyre Manufacturer Association states that those area above considered major repair, and is required to be repaired by professional or remolded. 

A. Internal patch can resolve everything

Two separate people enquired about internal patch, saying that isn't internal patch can patch any area?

If I say yes, you will expect a really high price for this internal patch.

90% of the time, I normally ask vehicle owners to let me try for internal patch, normally at those near the sidewall. A person even asked me to try patching the sidewall and willing to pay even if I may fail to repair it. I patched 3 of them and succeeded.

B. Still leaking even without air, and after patch

Not all areas can be patched even at the tread area. Especially air is still leaking out even the tyre is without air inside.

(Air leaking area, video below)

(Bubble still coming out without air pressure inside)
The same thing has happened to a private vehicle tyre

(Bubble still popping after patch, and tyre without air)
        

In this situation, I believe all ppl will consider it as fail to patch. But, could it be just the air trapped inside at the hole area?